Method of manufacturing semiconductor device, substrate processing apparatus, and recording medium

ABSTRACT

A method of manufacturing a semiconductor device includes forming a thin film containing a predetermined element, oxygen, carbon, and nitrogen on a substrate by performing a cycle a predetermined number of times after supplying a nitriding gas to the substrate. The cycle includes performing the following steps in the following order: supplying a carbon-containing gas to the substrate; supplying a predetermined element-containing gas to the substrate; supplying the carbon-containing gas to the substrate; supplying an oxidizing gas to the substrate; and supplying the nitriding gas to the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2012-205073, filed on Sep. 18, 2012, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a method of manufacturing asemiconductor device which includes a process of forming a thin film ona substrate, a substrate processing apparatus, and a recording medium.

BACKGROUND

As semiconductor devices are miniaturized in size, the demand forreducing a parasitic capacitance between a gate and a source of atransistor is increasing. For this reason, a film (e.g., a low-k film)having a relatively lower dielectric constant is considered inmanufacturing semiconductor devices, instead of a silicon nitride film(i.e., Si_(x)N_(y) film, hereinafter, simply referred to as “SiN film”),which is conventionally used as a sidewall film or the like. In asilicon oxycarbonitride film (SiOCN film) in which oxygen (O) and carbon(C) are added to the SiN film, a low dielectric constant is realized byadding O, and a wet etching resistance or a dry etching resistance whichis deteriorated by adding O can be recovered or improved by adding C.

It is known that the SiOCN film, which is a thin film containing apredetermined element such as silicon, oxygen, carbon and nitrogen, isformed, for example, by performing a cycle a predetermined number oftimes, the cycle including: supplying a silicon-containing gas to aheated wafer in a process chamber; supplying a carbon-containing gas;supplying a nitriding gas; and supplying an oxidizing gas.

Recently, since a high dielectric constant insulating film (high-k film)is used as a gate insulating film of transistors, it is increasinglyrequired that the film forming temperature of a thin film formed near agate, such as a sidewall film, is lowered to a low temperature range,for example, of 600 degrees C. or less, or 450 degrees C. or less.However, when the film forming temperature is lowered to such a lowtemperature range, a film forming rate of a thin film is reduced,causing a low productivity of semiconductor devices.

Also, if the film forming temperature of the SiOCN film is lowered, insome cases, an oxygen (O) concentration and a carbon (C) concentrationare respectively reduced, and a nitrogen (N) concentration is increasedas the film forming temperature is lowered. That is, in some cases, acomposition of the SiOCN film approaches that of the SiN film, therebyincreasing the dielectric constant of the SiOCN film.

SUMMARY

The present disclosure provides some embodiments of a method ofmanufacturing a semiconductor device, a substrate processing apparatusand a recording medium, which make it possible to suppress a reductionin film forming rate and an increase in dielectric constant when a thinfilm containing a predetermined element, oxygen, carbon and nitrogen isformed in a low temperature range.

According to some embodiments of the present disclosure, there isprovided a method of manufacturing a semiconductor device, includingforming a thin film containing a predetermined element, oxygen, carbon,and nitrogen on a substrate by performing a cycle a predetermined numberof times after supplying a nitriding gas to the substrate, the cycleincluding performing the following steps in the following order:

supplying a carbon-containing gas to the substrate;

supplying a predetermined element-containing gas to the substrate;

supplying the carbon-containing gas to the substrate;

supplying an oxidizing gas to the substrate; and

supplying the nitriding gas to the substrate.

According to some other embodiments of the present disclosure, there isprovided a substrate processing apparatus, including:

a process chamber configured to accommodate a substrate;

a predetermined element-containing gas supply system configured tosupply a predetermined element-containing gas to the substrate in theprocess chamber;

a carbon-containing gas supply system configured to supply acarbon-containing gas to the substrate in the process chamber;

an oxidizing gas supply system configured to supply an oxidizing gas tothe substrate in the process chamber;

a nitriding gas supply system configured to supply a nitriding gas tothe substrate in the process chamber; and

a control unit configured to control the predeterminedelement-containing gas supply system, the carbon-containing gas supplysystem, the oxidizing gas supply system and the nitriding gas supplysystem such that a thin film containing the predetermined element,oxygen, carbon, and nitrogen is formed on the substrate in the processchamber by performing a cycle a predetermined number of times aftersupplying the nitriding gas to the substrate in the process chamber, thecycle including performing the following steps in the following order:supplying the carbon-containing gas to the substrate in the processchamber; supplying the predetermined element-containing gas to thesubstrate in the process chamber; supplying the carbon-containing gas tothe substrate in the process chamber; supplying the oxidizing gas to thesubstrate in the process chamber; and supplying the nitriding gas to thesubstrate in the process chamber.

According to yet other embodiments of the present disclosure, there isprovided a non-transitory computer-readable recording medium storing aprogram that causes a computer to perform a process of forming a thinfilm containing a predetermined element, oxygen, carbon, and nitrogen ona substrate in a process chamber by performing a cycle a predeterminednumber of times after supplying a nitriding gas to the substrate in theprocess chamber, the cycle including performing the following steps inthe following order:

supplying a carbon-containing gas to the substrate in the processchamber;

supplying a predetermined element-containing gas to the substrate in theprocess chamber;

supplying the carbon-containing gas to the substrate in the processchamber;

supplying an oxidizing gas to the substrate in the process chamber; and

supplying the nitriding gas to the substrate in the process chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a configuration of a verticalprocessing furnace of a substrate processing apparatus, in which aportion of the processing furnace is shown in a longitudinal sectionalview, according to some embodiments.

FIG. 2 is a schematic view illustrating a configuration of the verticalprocessing furnace of the substrate processing apparatus, in which aportion of the processing furnace is shown in a sectional view takenalong line A-A in FIG. 1.

FIG. 3 is a schematic view illustrating a configuration of a controllerof the substrate processing apparatus according to some embodiments.

FIGS. 4A and 4B are views illustrating gas supply timings in a firstsequence and gas supply timings in a modification of the first sequence,respectively, according to an embodiment.

FIGS. 5A and 5B are views illustrating gas supply timings in a secondsequence and gas supply timings in a modification of the secondsequence, respectively, according to the embodiment.

FIGS. 6A and 6B are views illustrating gas supply timings in an exampleof the present disclosure and gas supply timings in a reference example,respectively.

FIG. 7 is a view showing evaluation results of a composition of a SiOCNfilm in Example 1.

FIG. 8 is a view showing evaluation results of a composition of a SiOCNfilm in Example 2.

FIG. 9 is a view showing evaluation results of a composition of a SiOCNfilm in Reference Example 1.

FIG. 10 is a view showing evaluation results of a composition of a SiOCNfilm in Reference Example 2.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying drawings. In the followingdetailed description, numerous specific details are set forth in orderto provide a thorough understanding of the present invention(s).However, it will be apparent to one of ordinary skill in the art thatthe present invention(s) may be practiced without these specificdetails. In other instances, well-known methods, procedures, systems,and components have not been described in detail so as not tounnecessarily obscure aspects of the various embodiments.

Embodiment of the Present Disclosure

Hereinafter, embodiments of the present disclosure will now be describedwith reference to the drawings.

(1) Configuration of Substrate Processing Apparatus

FIG. 1 is a schematic view illustrating a configuration of a verticalprocessing furnace 202 of a substrate processing apparatus, according tosome embodiments, in which a portion of the processing furnace is shownin a longitudinal sectional view. FIG. 2 is a schematic viewillustrating a configuration of the vertical processing furnace 202 ofthe substrate processing apparatus, according to some embodiments, inwhich a portion of the processing furnace is shown in a sectional viewtaken along line A-A in FIG. 1. The present disclosure is not limited tothe substrate processing apparatus according to these embodiments, butmay be applied to other substrate processing apparatuses having aprocessing furnace of a single wafer type, a hot wall type, a cold walltype, and the like.

As shown in FIG. 1, the vertical processing furnace 202 has a heater 207as a heating unit (heating mechanism). The heater 207 has a cylindricalshape and is supported by a heater base (not shown) as a support plateso as to be vertically installed. The heater 207 acts as an activatingmechanism to activate gas by heat, as described later.

A reaction tube 203 defining a reaction vessel (process vessel) isdisposed inside the heater 207 in a concentric form along the heater207. The reaction tube 203 is made of a heat resistant material such asquartz (SiO₂) or silicon carbide (SiC) and has a cylindrical shape withits upper end closed and its lower end opened. A process chamber 201 isprovided in a hollow cylindrical portion of the reaction tube 203 and isconfigured to accommodate a plurality of wafers 200. The wafers 200 arehorizontally stacked in multiple stages to be aligned in a verticaldirection in a boat 217 described later.

A first nozzle 249 a, a second nozzle 249 b, a third nozzle 249 c and afourth nozzle 249 d are provided in the process chamber 201 to penetratethrough a lower portion of the reaction tube 203. The first nozzle 249a, the second nozzle 249 b, the third nozzle 249 c and the fourth nozzle249 d are respectively connected to a first gas supply pipe 232 a, asecond gas supply pipe 232 b, a third gas supply pipe 232 c and a fourthgas supply pipe 232 d. In this way, the four nozzles 249 a, 249 b, 249 cand 249 d and the four gas supply pipes 232 a, 232 b, 232 c and 232 dare provided in the reaction tube 203 to allow several types of (four inthis example) gases to be supplied into the process chamber 201.

Moreover, a manifold (not shown) formed of metal which supports thereaction tube 203 may be installed under the reaction tube 203 such thatthe nozzles penetrate through a sidewall of the metal manifold. In thiscase, an exhaust pipe 231 described later may be further installed atthe metal manifold. Also, the exhaust pipe 231 may be installed at alower portion of the reaction tube 203 rather than at the metalmanifold. In this way, a furnace port of the processing furnace 202 maybe formed of metal, and the nozzles may be mounted to the metal furnaceport.

A mass flow controller (MFC) 241 a, which is a flow rate controller (aflow rate control part), and a valve 243 a, which is an opening/closingvalve, are installed in the first gas supply pipe 232 a in this orderfrom an upstream direction. In addition, a first inert gas supply pipe232 e is connected to the first gas supply pipe 232 a at a downstreamside of the valve 243 a. A mass flow controller 241 e, which is a flowrate controller (a flow rate control part), and a valve 243 e, which isan opening/closing valve, are installed at the first inert gas supplypipe 232 e in this order from an upstream direction. In addition, theabove-described first nozzle 249 a is connected to a leading end portionof the first gas supply pipe 232 a. The first nozzle 249 a is installedin an arc-shaped space between an inner wall of the reaction tube 203and the wafers 200. The first nozzle 249 a is vertically disposed alongthe inner wall of the reaction tube 203 to rise upward in a stackingdirection of the wafers 200. That is, the first nozzle 249 a isinstalled at a side of a wafer arrangement region, in which the wafers200 are arranged. The first nozzle 249 a is configured as an L-shapedlong nozzle and has its horizontal portion installed to penetratethrough a lower sidewall of the reaction tube 203 and its verticalportion installed to rise from one end portion of the wafer arrangementregion toward the other end portion thereof. A plurality of gas supplyholes 250 a through which gas is supplied is formed in a side surface ofthe first nozzle 249 a. The gas supply holes 250 a are opened toward acenter of the reaction tube 203 to supply gas toward the wafers 200. Thegas supply holes 250 a are disposed at a predetermined opening pitchfrom a lower portion to an upper portion of the reaction tube 203. Thegas supply holes 250 a have the same opening area. A first gas supplysystem is mainly configured by the first gas supply pipe 232 a, the massflow controller 241 a and the valve 243 a. The first nozzle 249 a mayalso be included in the first gas supply system. In addition, a firstinert gas supply system is mainly configured by the first inert gassupply pipe 232 e, the mass flow controller 241 e and the valve 243 e.The first inert gas supply system also functions as a purge gas supplysystem.

A mass flow controller (MFC) 241 b, which is a flow rate controller (aflow rate control part), and a valve 243 b, which is an opening/closingvalve, are installed in the second gas supply pipe 232 b in this orderfrom the upstream direction. In addition, a second inert gas supply pipe232 f is connected to the second gas supply pipe 232 b at a downstreamside of the valve 243 b. A mass flow controller 241 f, which is a flowrate controller (a flow rate control part), and a valve 243 f, which isan opening/closing valve, are installed at the second inert gas supplypipe 232 f in this order from the upstream direction. In addition, theabove-described second nozzle 249 b is connected to a leading endportion of the second gas supply pipe 232 b. The second nozzle 249 b isinstalled in an arc-shaped space between the inner wall of the reactiontube 203 and the wafers 200. The second nozzle 249 b is verticallydisposed along the inner wall of the reaction tube 203 to rise upward inthe stacking direction of the wafers 200. That is, the second nozzle 249b is installed at the side of the wafer arrangement region, in which thewafers 200 are arranged. The second nozzle 249 b is configured as anL-shaped long nozzle and has its horizontal portion installed topenetrate through the lower sidewall of the reaction tube 203 and itsvertical portion installed to rise from one end portion of the waferarrangement region toward the other end portion thereof. A plurality ofgas supply holes 250 b through which the gas is supplied is formed in aside surface of the second nozzle 249 b. The gas supply holes 250 b areopened toward the center of the reaction tube 203 to supply gas towardthe wafers 200. The gas supply holes 250 b are disposed at predeterminedopening pitch from the lower portion to the upper portion of thereaction tube 203. The gas supply holes 250 b have the same openingarea. A second gas supply system is mainly configured by the second gassupply pipe 232 b, the mass flow controller 241 b and the valve 243 b.The second nozzle 249 b may also be included in the second gas supplysystem. In addition, a second inert gas supply system is mainlyconfigured by the second inert gas supply pipe 232 f, the mass flowcontroller 241 f and the valve 243 f. The second inert gas supply systemalso functions as a purge gas supply system.

A mass flow controller (MFC) 241 c, which is a flow rate controller (aflow rate control part), and a valve 243 c, which is an opening/closingvalve, are installed in the third gas supply pipe 232 c in this orderfrom the upstream direction. In addition, a third inert gas supply pipe232 g is connected to the third gas supply pipe 232 c at a downstreamside of the valve 243 c. Amass flow controller 241 g, which is a flowrate controller (a flow rate control part), and a valve 243 g, which isan opening/closing valve, are installed at the third inert gas supplypipe 232 g in this order from the upstream direction. In addition, theabove-described third nozzle 249 c is connected to a leading end portionof the third gas supply pipe 232 c. The third nozzle 249 c is installedin an arc-shaped space between the inner wall of the reaction tube 203and the wafers 200. The third nozzle 249 c is vertically disposed alongthe inner wall of the reaction tube 203 to rise upward in the stackingdirection of the wafers 200. That is, the third nozzle 249 c isinstalled at the side of the wafer arrangement region, in which thewafers 200 are arranged. The third nozzle 249 c is configured as anL-shaped long nozzle and has its horizontal portion installed topenetrate through the lower sidewall of the reaction tube 203 and itsvertical portion installed to rise from at least one end portion of thewafer arrangement region toward the other end portion thereof. Aplurality of gas supply holes 250 c through which gas is supplied isformed in a side surface of the third nozzle 249 c. The gas supply holes250 c are opened toward the center of the reaction tube 203 to supplygas toward the wafers 200. The gas supply holes 250 c are disposed at apredetermined opening pitch from the lower portion to the upper portionof the reaction tube 203. The gas supply holes 250 c have the sameopening area. A third gas supply system is mainly configured by thethird gas supply pipe 232 c, the mass flow controller 241 c and thevalve 243 c. The third nozzle 249 c may also be included in the thirdgas supply system. In addition, a third inert gas supply system ismainly configured by the third inert gas supply pipe 232 g, the massflow controller 241 g and the valve 243 g. The third inert gas supplysystem also functions as a purge gas supply system.

A mass flow controller (MFC) 241 d, which is a flow rate controller (aflow rate control part), and a valve 243 d, which is an opening/closingvalve, are installed in the fourth gas supply pipe 232 d in this orderfrom the upstream direction. In addition, a fourth inert gas supply pipe232 h is connected to the fourth gas supply pipe 232 d at a downstreamside of the valve 243 d. A mass flow controller 241 h, which is a flowrate controller (a flow rate control part), and a valve 243 h, which isan opening/closing valve, are installed at the fourth inert gas supplypipe 232 h in this order from the upstream direction. In addition, theabove-described fourth nozzle 249 d is connected to a leading endportion of the fourth gas supply pipe 232 d. The fourth nozzle 249 d isinstalled inside a buffer chamber 237 that is a gas diffusion space.

The buffer chamber 237 is installed in an arc-shaped space between theinner wall of the reaction tube 203 and the wafers 200. The bufferchamber 237 is vertically disposed along the inner wall of the reactiontube 203 in the stacking direction of the wafers 200. That is, thebuffer chamber 237 is installed at the side of the wafer arrangementregion, in which the wafers 200 are arranged. A plurality of gas supplyholes 250 e through which gas is supplied is formed in an end portion ofa wall of the buffer chamber 237 adjacent to the wafers 200. The gassupply holes 250 e are opened toward the center of the reaction tube 203to supply gas toward the wafers 200. The gas supply holes 250 e aredisposed at a predetermined opening pitch from the lower portion to theupper portion of the reaction tube 203. The gas supply holes 250 e havethe same opening area.

The fourth nozzle 249 d is installed along the inner wall of thereaction tube 203 to rise upward in the stacking direction of the wafers200 in an end portion of the buffer chamber 237 opposite to the endportion thereof in which the gas supply holes 250 e is formed. That is,the fourth nozzle 249 d is installed at the side of the waferarrangement region, in which the wafers 200 are arranged. The fourthnozzle 249 d is configured as an L-shaped long nozzle and has itshorizontal portion installed to penetrate through the lower sidewall ofthe reaction tube 203 and its vertical portion installed to rise fromone end portion of the wafer arrangement region toward the other endportion thereof. A plurality of gas supply holes 250 d through which gasis supplied is formed in a side surface of the fourth nozzle 249 d. Thegas supply holes 250 d are opened toward the center of the bufferchamber 237. The gas supply holes 250 d are disposed at a predeterminedopening pitch from the lower portion to the upper portion of thereaction tube 203 in the same way as the gas supply holes 250 e of thebuffer chamber 237. The plurality of gas supply holes 250 d may have thesame opening area and the same opening pitch from an upstream side(lower portion) to an downstream side (upper portion) when a pressuredifference between the interior of the buffer chamber 237 and theinterior of the process chamber 201 is small. However, when the pressuredifference is large, the opening area of each gas supply hole 250 d maybe set larger and the opening pitch of each gas supply hole 250 d may beset smaller at the downstream side than the upstream side.

In the embodiment, by adjusting the opening area or opening pitch ofeach gas supply hole 250 d of the fourth nozzle 249 d from the upstreamside to the downstream side as described above, gases may be ejected atan almost same flow rate from the respective gas supply holes 250 ddespite a flow velocity difference. In addition, the gases ejected fromthe respective gas supply holes 250 d are first introduced into thebuffer chamber 237, and a flow velocity difference of the gases becomesuniform in the buffer chamber 237. That is, particle velocity of thegases ejected from the respective gas supply holes 250 d of the fourthnozzle 249 d into the buffer chamber 237 are reduced in the bufferchamber 237, and then are ejected from the respective gas supply holes250 e of the buffer chamber 237 into the process chamber 201. Therefore,the gases ejected from the respective gas supply holes 250 d of thefourth nozzle 249 d into the buffer chamber 237 have a uniform flow rateand flow velocity when the gases are ejected from the respective gassupply holes 250 e of the buffer chamber 237 into the process chamber201.

A fourth gas supply system is mainly configured by the fourth gas supplypipe 232 d, the mass flow controller 241 d, and the valve 243 d. Also,the fourth nozzle 249 d and the buffer chamber 237 may be included inthe fourth gas supply system. In addition, a fourth inert gas supplysystem is mainly configured by the fourth inert gas supply pipe 232 h,the mass flow controller 241 h, and the valve 243 h. The fourth inertgas supply system also functions as a purge gas supply system.

In the method of supplying gas according to the embodiment, the gas maybe transferred through the nozzles 249 a, 249 b, 249 c and 249 d and thebuffer chamber 237 disposed in an arc-shaped longitudinal space definedby the inner wall of the reaction tube 203 and end portions of thestacked wafers 200 The gas is first ejected into the reaction tube 203near the wafers 200 through the gas supply holes 250 a, 250 b, 250 c,250 d and 250 e opened in the nozzles 249 a, 249 b, 249 c, and 249 d andbuffer chamber 237, respectively. Thus, a main flow of the gas in thereaction tube 203 follows a direction parallel to surfaces of the wafers200, i.e., the horizontal direction. With this configuration, the gascan be uniformly supplied to the respective wafers 200, and thus, a filmthickness of a thin film formed on each of the wafers 200 can beuniform. In addition, a residual gas after the reaction flows toward anexhaust port, i.e., the exhaust pipe 231, but a flow direction of theresidual gas is not limited to the vertical direction but may beappropriately adjusted by a position of the exhaust port.

As a predetermined element-containing gas, a silicon precursor gas suchas a silane-based gas, i.e., a gas containing silicon (Si) that is thepredetermined element (silicon-containing gas), for example, is suppliedfrom the first gas supply pipe 232 a into the process chamber 201through the mass flow controller 241 a, the valve 243 a and the firstnozzle 249 a. The silicon-containing gas may include, for example,hexachlorodisilane (Si₂Cl₆, abbreviated to HCDS) gas. When a liquidprecursor in a liquid state under normal temperature and pressure, suchas HCDS, is used, the liquid precursor is vaporized by a vaporizationsystem, such as a vaporizer or a bubbler, and supplied as a precursorgas (HCDS gas).

A carbon-containing gas, i.e., a gas containing carbon (C) is suppliedfrom the second gas supply pipe 232 b into the process chamber 201through the mass flow controller 241 b, the valve 243 b, and the secondnozzle 249 b. The carbon-containing gas may include, for example, ahydrocarbon-based gas such as propylene (C₃H₆) gas.

An oxidizing gas, i.e., a gas containing oxygen (O) (oxygen-containinggas) is supplied from the third gas supply pipe 232 c into the processchamber 201 through the mass flow controller 241 c, the valve 243 c, andthe third nozzle 249 c. The oxidizing gas may include, for example,oxygen (O₂) gas.

A nitriding gas, i.e., a gas containing nitrogen (N)(nitrogen-containing gas) is supplied from the fourth gas supply pipe232 d into the process chamber 201 through the mass flow controller 241d, the valve 243 d, the fourth nozzle 249 d, the buffer chamber 237. Thenitriding gas may include, for example, ammonia (NH₃) gas.

A nitrogen (N₂) gas, for example, is supplied from the inert gas supplypipes 232 e, 232 f, 232 g and 232 h into the process chamber 201 throughthe mass flow controllers 241 e, 241 f, 241 g and 241 h, the valves 243e, 243 f, 243 g and 243 h, the gas supply pipes 232 a, 232 b, 232 c and232 d, the nozzles 249 a, 249 b, 249 c and 249 d, and the buffer chamber237, respectively.

Moreover, for example, when the above-described gases are allowed toflow through the respective gas supply pipes, a predeterminedelement-containing gas supply system, i.e., a silicon-containing gassupply system (silane-based gas supply system) is configured by thefirst gas supply system. In addition, a carbon-containing gas supplysystem, i.e., a hydrocarbon-based gas supply system is configured by thesecond gas supply system. Further, an oxidizing gas supply system, i.e.,an oxygen-containing gas supply system is configured by the third gassupply system. Furthermore, a nitriding gas supply system, i.e., anitrogen-containing gas supply system is configured by the fourth gassupply system. The predetermined element-containing gas supply systemmay also be referred to as “a precursor gas supply system,” or simply “aprecursor supply system.” Also, when the carbon-containing gas, theoxidizing gas and the nitriding gas may be generally simply referred toas “a reaction gas,” a reaction gas supply system is configured by thecarbon-containing gas supply system, the oxidizing gas supply system andthe nitriding gas supply system.

In the buffer chamber 237, as illustrated in FIG. 2, a first rod-shapedelectrode 269 that is a first electrode having an elongated structureand a second rod-shaped electrode 270 that is a second electrode havingan elongated structure are disposed to span from the lower portion tothe upper portion of the reaction tube 203 in the stacking direction ofthe wafers 200. Each of the first rod-shaped electrode 269 and thesecond rod-shaped electrode 270 is disposed in parallel to the fourthnozzle 249 d. Each of the first rod-shaped electrode 269 and the secondrod-shaped electrode 270 is covered with and protected by an electrodeprotection tube 275, which is a protection tube for protecting eachelectrode from an upper portion to a lower portion thereof. Any one ofthe first rod-shaped electrode 269 and the second rod-shaped electrode270 is connected to a high-frequency power source 273 through a matcher272, and the other one is connected to a ground corresponding to areference electric potential. By applying high-frequency power from thehigh-frequency power source 273 between the first rod-shaped electrode269 and the second rod-shaped electrode 270 through the matcher 272,plasma is generated in a plasma generation region 224 between the firstrod-shaped electrode 269 and the second rod-shaped electrode 270. Aplasma source as a plasma generator (plasma generating part) is mainlyconfigured by the first rod-shaped electrode 269, the second rod-shapedelectrode 270 and the electrode protection tubes 275. The matcher 272and the high-frequency power source 273 may also be included in theplasma source. Also, as described later, the plasma source functions asan activating mechanism (exciting part) that activates (excites) gas toplasma.

The electrode protection tube 275 has a structure in which each of thefirst rod-shaped electrode 269 and the second rod-shaped electrode 270can be inserted into the buffer chamber 237 in a state where each of thefirst rod-shaped electrode 269 and the second rod-shaped electrode 270is isolated from an internal atmosphere of the buffer chamber 237. Here,when an internal oxygen concentration of the electrode protection tube275 is equal to an oxygen concentration in an ambient air (atmosphere),each of the first rod-shaped electrode 269 and the second rod-shapedelectrode 270 inserted into the electrode protection tubes 275 isoxidized by the heat generated by the heater 207. Therefore, by chargingthe inside of the electrode protection tube 275 with an inert gas suchas nitrogen gas, or by purging the inside of the electrode protectiontube 275 with an inert gas such as nitrogen gas using an inert gaspurging mechanism, the internal oxygen concentration of the electrodeprotection tube 275 decreases, thereby preventing oxidation of the firstrod-shaped electrode 269 or the second rod-shaped electrode 270.

The exhaust pipe 231 for exhausting an internal atmosphere of theprocess chamber 201 is installed at the reaction tube 203. A vacuumexhaust device, for example, a vacuum pump 246, is connected to theexhaust pipe 231 through a pressure sensor 245, which is a pressuredetector (pressure detecting part) for detecting an internal pressure ofthe process chamber 201, and an auto pressure controller (APC) valve244, which is a pressure adjuster (pressure adjusting part). The APCvalve 244 is configured to perform/stop vacuum exhaust in the processchamber 201 by opening/closing the valve with the actuated vacuum pump246, and further to adjust the internal pressure of the process chamber201 by adjusting a degree of the valve opening with the actuated vacuumpump 246. An exhaust system is mainly configured by the exhaust pipe231, the APC valve 244, and the pressure sensor 245. Also, the vacuumpump 246 may be included in the exhaust system. The exhaust system isconfigured to adjust the degree of the valve opening of the APC valve244 based on pressure information detected by the pressure sensor 245while operating the vacuum pump 246 such that the internal pressure ofthe process chamber 201 is vacuum exhausted to a predetermined pressure(a vacuum level).

A seal cap 219, which functions as a furnace port cover configured tohermetically seal a lower end opening of the reaction tube 203, isinstalled under the reaction tube 203. The seal cap 219 is configured tocontact the lower end of the reaction tube 203 from the below in thevertical direction. The seal cap 219, for example, may be formed ofmetal such as stainless and have a disc shape. An O-ring 220, which is aseal member in contact with the lower end portion of the reaction tube203, is installed at an upper surface of the seal cap 219. A rotarymechanism 267 configured to rotate the boat 217, which is a substrateholder to be described later, is installed below the seal cap 219. Arotary shaft 255 of the rotary mechanism 267 passes through the seal cap219 to be connected to the boat 217. The rotary mechanism 267 isconfigured to rotate the wafers 200 by rotating the boat 217. The sealcap 219 is configured to be vertically elevated or lowered by a boatelevator 115, which is an elevation mechanism vertically disposed in theoutside of the reaction tube 203. The boat elevator 115 is configured toenable the boat 217 to be loaded into or unloaded from the processchamber 201 by elevating or lowering the seal cap 219. That is, the boatelevator 115 is configured as a transfer device (transfer mechanism)that transfers the boat 217, i.e., the wafers 200, into and out of theprocess chamber 201.

The boat 217, which is used as a substrate support, is made of a heatresistant material such as quartz or silicon carbide and is configuredto support a plurality of the wafers 200 horizontally stacked inmultiple stages with the centers of the wafers 200 concentricallyaligned. In addition, a heat insulating member 218 formed of a heatresistant material such as quartz or silicon carbide is installed at alower portion of the boat 217 and configured such that heat from theheater 207 cannot be transferred to the seal cap 219. In addition, theheat insulating member 218 may be configured by a plurality of heatinsulating plates formed of a heat resistant material such as quartz orsilicon carbide, and a heat insulating plate holder configured tosupport the heat insulating plates in a horizontal posture in amulti-stage manner.

A temperature sensor 263, which is a temperature detector, is installedin the reaction tube 203. Based on temperature information detected bythe temperature sensor 263, an electric conduction state to the heater207 is adjusted such that the interior of the process chamber 201 has adesired temperature distribution. The temperature sensor 263 isconfigured in an L-shape similar to the nozzles 249 a, 249 b, 249 c and249 d and installed along the inner wall of the reaction tube 203.

As illustrated in FIG. 3, a controller 121, which is a control unit(control part), is configured as a computer including a centralprocessing unit (CPU) 121 a, a random access memory (RAM) 121 b, amemory device 121 c, and an I/O port 121 d. The RAM 121 b, the memorydevice 121 c and the I/O port 121 d are configured to exchange data withthe CPU 121 a via an internal bus 121 e. An input/output device 122, forexample, including a touch panel or the like, is connected to thecontroller 121.

The memory device 121 c is configured by, for example, a flash memory, ahard disc drive (HDD), or the like. A control program for controllingoperation of the substrate processing apparatus or a process recipe, inwhich a sequence or condition for processing a substrate described lateris written, is readably stored in the memory device 121 c. Also, theprocess recipe functions as a program for the controller 121 to executeeach sequence in the substrate processing process, which will bedescribed later, to obtain a predetermined result. Hereinafter, theprocess recipe or control program may be generally referred to as “aprogram.” Also, when the term “program” is used herein, it may includethe case in which only the process recipe is included, the case in whichonly the control program is included, or the case in which both of theprocess recipe and the control program are included. In addition, theRAM 121 b is configured as a memory area (work area) in which a programor data read by the CPU 121 a is temporarily stored.

The I/O port 121 d is connected to the mass flow controllers 241 a, 241b, 241 c, 241 d, 241 e, 241 f, 241 g and 241 h, the valves 243 a, 243 b,243 c, 243 d, 243 e, 243 f, 243 g and 243 h, the pressure sensor 245,the APC valve 244, the vacuum pump 246, the heater 207, the temperaturesensor 263, the high-frequency power source 273, the matcher 272, therotary mechanism 267, the boat elevator 115 and the like.

The CPU 121 a is configured to read and execute the control program fromthe memory device 121 c. According to an input of an operation commandfrom the input/output device 122, the CPU 121 a reads the process recipefrom the memory device 121 c. In addition, the CPU 121 a is configuredto control the flow rate controlling operation of various types of gasesby the mass flow controllers 241 a, 241 b, 241 c, 241 d, 241 e, 241 f,241 g and 241 h, the opening/closing operation of the valves 243 a, 243b, 243 c, 243 d, 243 e, 243 f, 243 g and 243 h, the opening/closingoperation of the APC valve 244 and the pressure adjusting operation bythe APC valve 244 based on the pressure sensor 245, the operation ofstarting and stopping the vacuum pump 246, the temperature adjustingoperation of the heater 207 based on the temperature sensor 263, therotation and rotation speed adjusting operation of the boat 217 by therotary mechanism 267, the elevation operation of the boat 217 by theboat elevator 115, the operation of supplying power by thehigh-frequency power source 273, the impedance adjusting operation ofthe matcher 272, and the like according to contents of the read processrecipe.

Moreover, the controller 121 is not limited to being configured as adedicated computer but may be configured as a general-purpose computer.For example, the controller 121 according to the embodiment may beconfigured by preparing an external memory device 123 (for example, amagnetic tape, a magnetic disc such as a flexible disc or a hard disc,an optical disc such as a CD or DVD, a magneto-optical disc such as anMO, a semiconductor memory such as a USB memory or a memory card), inwhich the program is stored, and installing the program on thegeneral-purpose computer using the external memory device 123. Also, ameans for supplying a program to a computer is not limited to the casein which the program is supplied through the external memory device 123.For example, the program may be supplied using a communication meanssuch as the Internet or a dedicated line, rather than through theexternal memory device 123. Also, the memory device 121 c or theexternal memory device 123 is configured as a non-transitorycomputer-readable recording medium. Hereinafter, these means forsupplying the program will be simply referred to as “a recordingmedium.” In addition, when the term “recording medium” is used herein,it may include a case in which only the memory device 121 c is included,a case in which only the external memory device 123 is included, or acase in which both the memory device 121 c and the external memorydevice 123 are included.

(2) Substrate Processing Process

Next, an example of a sequence of forming a thin film on a substrate,which is one of the processes of manufacturing a semiconductor device byusing the processing furnace 202 of the above-described substrateprocessing apparatus, will be described. In addition, in the followingdescription, operations of the respective parts constituting thesubstrate processing apparatus are controlled by the controller 121.

Moreover, in the embodiment, in order to form a composition ratio of athin film to be formed as a stoichiometric composition or anotherpredetermined composition ratio different from the stoichiometriccomposition, supply conditions of a plurality of types of gasescontaining a plurality of elements constituting the film to be formedare controlled. For example, the supply conditions are controlled suchthat at least one element of a plurality of elements constituting thethin film to be formed stoichiometrically exceeds another element.Hereinafter, an example of a sequence of forming a film whilecontrolling a ratio of the plurality of elements constituting the thinfilm to be formed, i.e., a composition ratio of the film, will bedescribed.

(First Sequence)

First of all, a first sequence of the embodiment will be described.

FIG. 4A is a view illustrating gas supply timings in the first sequenceof the embodiment.

In the first sequence of the embodiment, a thin film containing apredetermined element, oxygen, carbon, and nitrogen is formed on a wafer200 by performing a cycle a predetermined number of times aftersupplying a nitriding gas to the wafer 200. The cycle includesperforming the following steps in the following order:

supplying a carbon-containing gas to the wafer 200;

supplying a predetermined element-containing gas to the wafer 200;

supplying the carbon-containing gas to the wafer 200;

supplying an oxidizing gas to the wafer 200; and

supplying the nitriding gas to the wafer 200.

Further, in the process of forming the thin film,

an uppermost surface of the wafer 200 is modified by supplying thenitriding gas to the wafer 200 before the cycle is performed apredetermined number of times.

Furthermore, in the act of forming the thin film,

a first carbon-containing layer is formed in a portion of the uppermostsurface of the wafer 200 modified by the nitriding gas by supplying thecarbon-containing gas to the wafer 200,

a predetermined element-containing layer is formed on the uppermostsurface of the wafer 200 modified by the nitriding gas and having thefirst carbon-containing layer formed in the portion thereof by supplyingthe predetermined element-containing gas to the wafer 200,

a second carbon-containing layer is formed on the predeterminedelement-containing layer by supplying the carbon-containing gas to thewafer 200,

a layer containing the predetermined element, oxygen and carbon isformed by supplying the oxidizing gas to the wafer 200 to oxidize alayer including the first carbon-containing layer, the predeterminedelement-containing layer and the second carbon-containing layer, and

a layer containing the predetermined element, oxygen, carbon andnitrogen is formed and an uppermost surface thereof is modified bysupplying the nitriding gas to the wafer 200 to nitride the layercontaining the predetermined element, oxygen and carbon.

Also, the first carbon-containing layer is formed by adsorbing thecarbon-containing gas onto the portion of the uppermost surface of thewafer 200 modified by the nitriding gas. Specifically, at least aportion of the first carbon-containing layer is formed by substitutingthe carbon-containing gas for a portion of the nitriding gas adsorbedonto at least a portion of the uppermost surface of the wafer 200modified by the nitriding gas.

Hereinafter, the first sequence of the embodiment will be described.According to the embodiment, HCDS gas that is a silicon-containing gasis used as the predetermined element-containing gas, C₃H₆ gas is used asthe carbon-containing gas, O₂ gas is used as the oxidizing gas, and NH₃gas is used as the nitriding gas, and a silicon oxycarbonitride film(SiOCN film) containing silicon, oxygen, carbon and nitrogen is formedon the wafer 200 by the film forming sequence of FIG. 4A, i.e., the filmforming sequence of performing a cycle a predetermined number of timesafter supplying the NH₃ gas, the cycle including performing thefollowing steps in the following order: supplying the C₃H₆ gas,supplying the HCDS gas, supplying the C₃H₆ gas, supplying the O₂ gas,and supplying the NH₃ gas.

Moreover, when the term “wafer” is used herein, it may refer to “thewafer itself” or “the wafer and a laminated body (a collected body) ofpredetermined layers or films formed on the surface of the wafer” (i.e.,the wafer including the predetermined layers or films formed on thesurface may be referred to as a wafer). In addition, the phrase “asurface of a wafer” as used herein may refer to “a surface (an exposedsurface) of a wafer itself” or “a surface of a predetermined layer orfilm formed on the wafer, i.e., the uppermost surface of the wafer,which is a laminated body.”

Accordingly, “a predetermined gas is supplied to a wafer” may mean that“a predetermined gas is directly supplied to a surface (an exposedsurface) of a wafer itself” or that “a predetermined gas is supplied toa layer or a film formed on a wafer, i.e., on the uppermost surface of awafer as a laminated body.” Also, “a predetermined layer (or film) isformed on a wafer” may mean that “a predetermined layer (or film) isdirectly formed on a surface (an exposed surface) of a wafer itself” orthat “a predetermined layer (or film) is formed on a layer or a filmformed on a wafer, i.e., on the uppermost surface of a wafer as alaminated body.”

Moreover, the term “substrate” as used herein may be synonymous with theterm “wafer,” and in this case, the terms “wafer” and “substrate” may beused interchangeably in the above description.

(Wafer Charging and Boat Loading)

When the plurality of wafers 200 are charged on the boat 217 (wafercharging), as illustrated in FIG. 1, the boat 217 supporting theplurality of wafers 200 is raised by the boat elevator 115 to be loadedinto the process chamber 201 (boat loading). In this state, the seal cap219 seals the lower end of the reaction tube 203 via the O-ring 220.

(Pressure Adjustment and Temperature Adjustment)

The interior of the process chamber 201 is vacuum exhausted by thevacuum pump 246 to a desired pressure (vacuum level). Here, the internalpressure of the process chamber 201 is measured by the pressure sensor245, and the APC valve 244 is feedback-controlled based on the measuredpressure information (pressure adjustment). Also, the vacuum pump 246maintains a regular operation state at least until the processing of thewafers 200 is terminated. Further, the process chamber 201 is heated bythe heater 207 to a desired temperature. Here, an electrical conductionstate to the heater 207 is feedback-controlled based on the temperatureinformation detected by the temperature sensor 263 until the interior ofthe process chamber 201 reaches a desired temperature distribution(temperature adjustment). In addition, heating of the interior of theprocess chamber 201 by the heater 207 is continuously performed at leastuntil processing of the wafers 200 is terminated. Next, the boat 217 andwafers 200 begin to be rotated by the rotary mechanism 267 (waferrotation). Furthermore, the rotation of the boat 217 and wafers 200 bythe rotary mechanism 267 is continuously performed at least untilprocessing of the wafers 200 is terminated.

[Process of Forming Silicon Oxycarbonitride Film]

Next, a surface modifying step described later is performed, and thenfive steps described later, i.e., Steps 1 to 5, are sequentiallyperformed.

[Surface Modifying Step] (NH₃ Gas Supply)

The valve 243 d of the fourth gas supply pipe 232 d is opened to flowNH₃ gas into the fourth gas supply pipe 232 d. A flow rate of the NH₃gas flowing into the fourth gas supply pipe 232 d is adjusted by themass flow controller 241 d. The flow rate-adjusted NH₃ gas is suppliedinto the buffer chamber 237 through the gas supply holes 250 d of thefourth nozzle 249 d. At this time, if no high-frequency power is appliedbetween the first rod-shaped electrode 269 and the second rod-shapedelectrode 270, the NH₃ gas supplied into the buffer chamber 237 isactivated by heat to be supplied into the process chamber 201 throughthe gas supply holes 250 e and exhausted through the exhaust pipe 231.In this way, the NH₃ gas activated by heat is supplied to the wafer 200.On the other hand, at this time, if high-frequency power is appliedbetween the first rod-shaped electrode 269 and the second rod-shapedelectrode 270, the NH₃ gas supplied into the buffer chamber 237 may beexcited to plasma to be supplied into the process chamber 201. In thiscase, the high-frequency power applied between the first rod-shapedelectrode 269 and the second rod-shaped electrode 270 from thehigh-frequency power source 273 is set to fall within a range of, forexample, 50 to 1000 W. The other processing conditions are set to beequal to processing conditions (described later) when the NH₃ gas isactivated by heat.

At the same time, the valve 243 h is opened to flow the N₂ gas into thefourth inert gas supply pipe 232 h. The N₂ gas flowing in the fourthinert gas supply pipe 232 h is supplied into the process chamber 201through the buffer chamber 237 together with the NH₃ gas, and exhaustedthrough the exhaust pipe 231. In order to prevent infiltration of theNH₃ gas into the first nozzle 249 a, the second nozzle 249 b, and thethird nozzle 249 c, the valves 243 e, 243 f and 243 g are opened to flowthe N₂ gas into the first inert gas supply pipe 232 e, the second inertgas supply pipe 232 f, and the third inert gas supply pipe 232 g. The N₂gas is supplied into the process chamber 201 through the first gassupply pipe 232 a, the second gas supply pipe 232 b, the third gassupply pipe 232 c, the first nozzle 249 a, the second nozzle 249 b, andthe third nozzle 249 c, and exhausted through the exhaust pipe 231.

When the NH₃ gas is activated by heat to be allowed to flow, the APCvalve 244 is appropriately adjusted to set the internal pressure of theprocess chamber 201 to fall within a range of, for example, 1 to 6000Pa. A supply flow rate of the NH₃ gas controlled by the mass flowcontroller 241 d is set to fall within a range of, for example, 100 to10000 sccm. A supply flow rate of the N₂ gas controlled by each of themass flow controllers 241 h, 241 e, 241 f and 241 g is set to fallwithin a range of, for example, 100 to 10000 sccm. Here, a partialpressure of the NH₃ gas in the process chamber 201 is set to fall withina range of, for example, 0.01 to 5941 Pa. A duration for supplying theNH₃ gas to the wafer 200, i.e., a gas supply time (irradiation time), isset to fall within a range of, for example, 1 to 600 seconds. Also, agas supply time of the NH₃ gas in the surface modification step may beset to be longer than a gas supply time of the NH₃ gas in Step 5described later. Accordingly, a surface modification processing(described later) may be sufficiently performed on the uppermost surfaceof the wafer 200 before a film is formed. Here, a temperature of theheater 207 is set such that a temperature of the wafer 200 falls withina range of, for example, 250 to 700 degrees C., or more specifically,for example, 300 to 650 degrees C. Since the NH₃ gas has a high reactiontemperature and is difficult to react at the above-described wafertemperature, it is possible to thermally activate the NH₃ gas by settingthe internal pressure of the process chamber 201 to the relatively highpressure as described above. In addition, since the NH₃ gas is activatedby heat and supplied to generate a soft reaction, the surfacemodification described later can be gently performed.

The uppermost surface (base surface when the SiOCN film is formed) ofthe wafer 200 is modified by supplying the activated NH₃ gas to theuppermost surface of the wafer 200 (surface modification processing).Specifically, the NH3 gas is adsorbed onto the uppermost surface of thewafer 200, an adsorption layer of the NH₃ gas is formed on the uppermostsurface of the wafer 200. At that time, the uppermost surface of thewafer 200 may react with the activated NH₃ gas to be nitrided, and thus,a layer having Si—N bonding, i.e., a nitride layer (silicon nitridelayer) containing silicon (Si) and nitrogen (N) may be further formed onthe uppermost surface of the wafer 200. That is, both the nitride layerand the adsorption layer of the NH₃ gas may be formed on the uppermostsurface of the wafer 200.

The adsorption layer of the NH₃ gas includes a chemisorption layer inwhich gas molecules of the NH₃ gas are discontinuous, in addition to achemisorption layer in which the gas molecules are continuous. That is,the adsorption layer of the NH₃ gas includes a chemisorption layerconstituted by NH₃ gas molecules having a thickness of one molecularlayer or less than one molecular layer. Also, the NH₃ gas moleculesconstituting the adsorption layer of the NH₃ gas contain molecules inwhich bonding of N and H is partially broken (N_(x)H_(y) molecules).That is, the adsorption layer of the NH₃ gas includes a chemisorptionlayer in which the NH₃ gas molecules and/or the N_(x)H_(y) molecules arecontinuous or a chemisorption layer in which the NH₃ gas moleculesand/or the N_(x)H_(y) molecules are discontinuous. Also, the nitridelayer includes a discontinuous layer as well as a continuous layercontaining Si and Cl. That is, the nitride layer includes a layerincluding Si—N bonding having a thickness of less than one atomic layerto several atomic layers. Also, a layer having a thickness of less thanone molecular layer refers to a discontinuously formed molecular layer,and a layer having a thickness of one molecular layer refers to acontinuously formed molecular layer. In addition, a layer having athickness of less than one atomic layer refers to a discontinuouslyformed atomic layer, and a layer having a thickness of one atomic layerrefers to a continuously formed atomic layer.

The uppermost surface of the wafer 200 after the surface modificationprocessing is performed becomes a surface state in which HCDS gassupplied in Step 2 described later is easily adsorbed and Si is easilydeposited. That is, the NH₃ gas used in the surface modification stepacts as an adsorption and deposition facilitating gas that facilitatesadsorption or deposition of the HCDS gas or Si onto the uppermostsurface of the wafer 200.

(Residual Gas Removal)

Thereafter, the valve 243 d of the fourth gas supply pipe 232 d isclosed to stop the supply of the NH₃ gas. At this time, while the APCvalve 244 of the exhaust pipe 231 is in an open state, the interior ofthe process chamber 201 is vacuum exhausted by the vacuum pump 246, andthe NH₃ gas remaining in the process chamber 201 which does not react orremains after contributing to the surface modification of the wafer 200or reaction byproducts are removed from the process chamber 201. At thistime, the valves 243 h, 243 e, 243 f and 243 g are in an open state, andthe supply of the N₂ gas into the process chamber 201 is maintained.Accordingly, the NH₃ gas remaining in the process chamber 201 which doesnot react or remains after contributing to the surface modification orreaction byproducts can be more effectively removed from the processchamber 201.

Moreover, in this case, the gas remaining in the process chamber 201 maynot be completely removed, and the interior of the process chamber 201may not be completely purged. When the gas remaining in the processchamber 201 is very small in amount, there is no adverse effectgenerated in Step 1 performed thereafter. Here, an amount of the N₂ gassupplied into the process chamber 201 need not be a large amount, andfor example, approximately the same amount of the N₂ gas as the reactiontube 203 (the process chamber 201) may be supplied to perform the purgesuch that there is no adverse effect generated in Step 1. As describedabove, as the interior of the process chamber 201 is not completelypurged, the purge time can be reduced, thereby improving the throughput.In addition, the consumption of the N₂ gas can also be suppressed to aminimal necessity.

The nitriding gas may include diazene (N₂H₂) gas, hydrazine (N₂H₄) gas,N₃H₈ gas, and the like, in addition to ammonia (NH₃) gas. The inert gasmay include a rare gas such as Ar gas, He gas, Ne gas, Xe gas, and thelike, in addition to the N2 gas.

[Step 1] (C₃H₆ Gas Supply)

After the surface modification step is terminated and the residual gasin the process chamber 201 is removed, the valve 243 b of the second gassupply pipe 232 b is opened to flow the C₃H₆ gas into the second gassupply pipe 232 b. A flow rate of the C₃H₆ gas flowing into the secondgas supply pipe 232 b is adjusted by the mass flow controller 241 b. Theflow rate-adjusted C₃H₆ gas is supplied into the process chamber 201through the gas supply holes 250 b of the second nozzle 249 b. The C₃H₆gas supplied into the process chamber 201 is activated by heat andexhausted through the exhaust pipe 231. Here, the C₃H₆ gas activated byheat is supplied to the wafer 200.

At the same time, the valve 243 f is opened to flow the N₂ gas into thesecond inert gas supply pipe 232 f. The N₂ gas flowing in the secondinert gas supply pipe 232 f is supplied into the process chamber 201together with the C₃H₆ gas, and exhausted through the exhaust pipe 231.In this case, in order to prevent infiltration of the C₃H₆ gas into thefirst nozzle 249 a, the third nozzle 249 c, the fourth nozzle 249 d, andthe buffer chamber 237, the valves 243 e, 243 g and 243 h are opened toflow the N₂ gas into the first inert gas supply pipe 232 e, the thirdinert gas supply pipe 232 g, and the fourth inert gas supply pipe 232 h.The N₂ gas is supplied into the process chamber 201 through the firstgas supply pipe 232 a, the third gas supply pipe 232 c, the fourth gassupply pipe 232 d, the first nozzle 249 a, the third nozzle 249 c, thefourth nozzle 249 d, and the buffer chamber 237, and exhausted throughthe exhaust pipe 231.

Further, the APC valve 244 is appropriately adjusted to set the internalpressure of the process chamber 201 to fall within a range of, forexample, 1 to 6000 Pa. A supply flow rate of the C₃H₆ gas controlled bythe mass flow controller 241 b is set to fall within a range of, forexample, 100 to 10000 sccm. A supply flow rate of the N₂ gas controlledby each of the mass flow controllers 241 f, 241 e, 241 g and 241 h isset to fall within a range of, for example, 100 to 10000 sccm. Here, apartial pressure of the C₃H₆ gas in the process chamber 201 is set tofall within a range of, for example, 0.01 to 5941 Pa. A duration forsupplying the C₃H₆ gas to the wafer 200, i.e., a gas supply time(irradiation time), is set to fall within a range of, for example, 1 to200 seconds, specifically, for example, 1 to 120 seconds, or morespecifically, for example, 1 to 60 seconds. In this case, in the sameway as the surface modification step, a temperature of the heater 207 isset such that a temperature of the wafer 200 is a temperature within arange of, for example, 250 to 700 degrees C., or more specifically, forexample, 300 to 650 degrees C. In addition, since the C₃H₆ gas isactivated by heat and supplied to generate a soft reaction, a firstcarbon-containing layer described later is easily formed.

The first carbon-containing layer is formed in a portion of theuppermost surface of the wafer 200 modified by the NH₃ gas in thesurface modification step, by supplying the wafer 200 with the C₃H₆ gasactivated by heat. At least a portion of the first carbon-containinglayer is formed in such a manner that a portion of the NH₃ gas adsorbedonto at least a portion of the uppermost surface of the wafer 200modified by the NH₃ gas in the surface modification step is substitutedby the C₃H₆ gas. That is, at least the portion of the firstcarbon-containing layer is formed in such a manner that a portion of theNH₃ gas constituting the adsorption layer of the NH₃ gas formed on theuppermost surface of the wafer 200 in the surface modification step isdesorbed from the uppermost surface of the wafer 200 by the energy ofthe activated C₃H₆ gas and then the C₃H₆ gas is chemisorbed onto theportion in which the NH₃ gas is desorbed from the uppermost surface ofthe wafer 200. Here, in addition to the chemisorption layer of the C₃H₆gas, a chemisorption layer of a substance (C_(x)H_(y)) produced bydecomposing the C₃H₆ or a carbon layer (C layer) may be formed, whichmay be considered as being included in a portion of the firstcarbon-containing layer.

At this time, the C₃H₆ gas may be adsorbed onto a portion of theuppermost surface of the wafer 200 without substituting the NH₃ gas withthe C₃H₆ gas, i.e., without desorbing the NH₃ gas from the uppermostsurface of the wafer 200. For example, a portion of the C₃H₆ gassupplied to the wafer 200 may be adsorbed onto the adsorption layer ofthe NH₃ gas formed on the uppermost surface of the wafer 200 in thesurface modification step. In addition, a portion of the C₃H₆ gassupplied to the wafer 200 may be adsorbed onto the nitride layer formedon the uppermost surface of the wafer 200 in the surface modificationstep. Further, a portion of the C₃H₆ gas supplied to the wafer 200 maybe adsorbed onto a portion of the uppermost surface of the wafer 200 inwhich the nitride layer or the adsorption layer of the NH₃ gas is notformed. In this way, in some cases, the C₃H₆ gas is adsorbed onto aportion of the uppermost surface of the wafer 200 without substitutingthe NH₃ gas with the C₃H₆ gas, which may be considered as being includedin a portion of the first carbon-containing layer. Also, even in such acase, without limitation to the chemisorption layer of the C₃H₆ gas, achemisorption layer of a substance (C_(x)H_(y)) produced by decomposingC₃H₆ or a carbon layer (C layer) may also be formed, which may beconsidered as being included in a portion of the first carbon-containinglayer.

Under the above-described processing conditions, the adsorption of theC₃H₆ gas accompanied by the substitution of the NH₃ gas with the C₃H₆gas leads to the adsorption accompanied by the substitution (desorption)of not all but a portion of the NH₃ gas constituting the adsorptionlayer of the NH₃ gas. That is, all the NH₃ gas constituting theadsorption layer of the NH₃ gas is not substituted (desorbed), and aportion thereof maintains the adsorption state. In addition, theadsorption of the C₃H₆ gas not accompanied by the substitution of theNH₃ gas with the C₃H₆ gas becomes not continuous adsorption (saturatedadsorption), which makes the uppermost surface of the wafer 200 beentirely covered, but discontinuous adsorption (unsaturated adsorption).Accordingly, the first carbon-containing layer formed in Step 1 becomesa layer having a thickness of less than one molecular layer, i.e., adiscontinuous layer to cover only a portion of the uppermost surface ofthe wafer 200 modified by the NH₃ gas in the surface modification step.That is, the other portion of the uppermost surface of the wafer 200modified by the NH₃ gas in the surface modification step is not coveredwith the first carbon-containing layer but intactly exposed even afterthe first carbon-containing layer is formed in Step 1, so that the otherportion maintains a surface state where the HCDS gas supplied in Step 2described later is easily adsorbed and Si is easily deposited.

For the adsorption of the C₃H₆ gas onto the uppermost surface of thewafer 200 to be unsaturated, the processing conditions in Step 1 needonly be set to the above-described processing conditions. However, ifthe processing conditions in Step 1 are set to the following processingconditions, it becomes easy to unsaturate the adsorption of the C₃H₆ gasonto the uppermost surface of the wafer 200.

Wafer Temperature: 500 to 650 degrees C.

Internal Pressure of Process Chamber: 133 to 5332 Pa

Partial Pressure of C₃H₆ Gas: 33 to 5177 Pa

Supply Flow Rate of C₃H₆ Gas: 1000 to 10000 sccm

Supply Flow Rate of N₂ Gas: 300 to 3000 sccm

Supply Time of C₃H₆ Gas: 6 to 200 seconds

(Residual Gas Removal)

After the first carbon-containing layer is formed, the valve 243 b ofthe second gas supply pipe 232 b is closed to stop the supply of theC₃H₆ gas. At this time, while the APC valve 244 of the exhaust pipe 231is in an open state, the interior of the process chamber 201 is vacuumexhausted by the vacuum pump 246, and the C₃H₆ gas remaining in theprocess chamber 201 which does not react, reaction byproducts, or theNH₃ gas desorbed from the uppermost surface of the wafer 200 is removedfrom the process chamber 201. At this time, the valves 243 f, 243 e, 243g and 243 f are in an open state, and the supply of the N₂ gas as theinert gas into the process chamber 201 is maintained. The N₂ gas acts asa purge gas, and thus, the C₃H₆ gas remaining in the process chamber 201which does not react, reaction byproducts, or the NH₃ gas desorbed fromthe uppermost surface of the wafer 200 can be more effectively removedfrom the process chamber 201.

Moreover, in this case, the gas remaining in the process chamber 201 maynot be completely removed, and the interior of the process chamber 201may not be completely purged. When the gas remaining in the processchamber 201 is very small in amount, there is no adverse effectgenerated in Step 2 performed thereafter. Here, an amount of the N₂ gassupplied into the process chamber 201 need not be a large amount, andfor example, approximately the same amount of the N₂ gas as the reactiontube 203 (the process chamber 201) may be supplied to perform the purgesuch that there is no adverse effect generated in Step 2. As describedabove, as the interior of the process chamber 201 is not completelypurged, the purge time can be reduced, thereby improving the throughput.In addition, the consumption of the N₂ gas can also be suppressed to aminimal necessity.

The carbon-containing gas may include a hydrocarbon-based gas, such asacetylene (C₂H₂) gas or ethylene (C₂H₄) gas, in addition to thepropylene (C₃H₆) gas.

[Step 2] (HCDS Gas Supply)

After Step 1 is terminated and the residual gas in the process chamber201 is removed, the valve 243 a of the first gas supply pipe 232 a isopened to flow the HCDS gas into the first gas supply pipe 232 a. A flowrate of the HCDS gas flowing into the first gas supply pipe 232 a isadjusted by the mass flow controller 241 a. The flow rate-adjusted HCDSgas is supplied into the process chamber 201 through the gas supplyholes 250 a of the first nozzle 249 a, and exhausted through the exhaustpipe 231. In this way, the HCDS gas is supplied to the wafer 200.

At the same time, the valve 243 e is opened to flow the inert gas suchas the N₂ gas into the first inert gas supply pipe 232 e. A flow rate ofthe N₂ gas flowing in the first inert gas supply pipe 232 e is adjustedby the mass flow controller 241 e. The flow rate-adjusted N₂ gas issupplied into the process chamber 201 together with the HCDS gas, andexhausted through the exhaust pipe 231. Here, in order to preventinfiltration of the HCDS gas into the second nozzle 249 b, the thirdnozzle 249 c, the fourth nozzle 249 d and the buffer chamber 237, thevalves 243 f, 243 g and 243 h are opened to flow the N₂ gas into thesecond inert gas supply pipe 232 f, the third inert gas supply pipe 232g, and the fourth inert gas supply pipe 232 h. The N₂ gas is suppliedinto the process chamber 201 through the second gas supply pipe 232 b,the third gas supply pipe 232 c, the fourth gas supply pipe 232 d, thesecond nozzle 249 b, the third nozzle 249 c, the fourth nozzle 249 d andthe buffer chamber 237, and exhausted through the exhaust pipe 231.

In this case, the APC valve 244 is appropriately adjusted to set theinternal pressure of the process chamber 201 to fall within a range of,for example, 1 to 13300 Pa, or more specifically, for example, 20 to1330 Pa. A supply flow rate of the HCDS gas controlled by the mass flowcontroller 241 a is set to fall within a range of, for example, 1 to1000 sccm. A supply flow rate of the N₂ gas controlled by each of themass flow controllers 241 e, 241 f, 241 g and 241 h is set to fallwithin a range of, for example, 100 to 10000 sccm. A duration forsupplying the HCDS gas to the wafer 200, i.e., a gas supply time(irradiation time), is set to fall within a range of, for example, 1 to200 seconds, specifically, for example, 1 to 120 seconds, or morespecifically, for example, 1 to 60 seconds. At this time, a temperatureof the heater 207 is the same temperature as in Step 1 and is set suchthat a CVD reaction is generated in the process chamber 210, i.e., atemperature of the wafer 200 becomes to fall within a range of, forexample, 250 to 700 degrees C., or more specifically, for example, 300to 650 degrees C. Also, when the temperature of the wafer 200 is lessthan 250 degrees C., the HCDS gas cannot be easily adsorbed onto thewafer 200 such that a practical film forming rate cannot be obtained.This problem can be solved by increasing the temperature of the wafer200 to 250 degrees C. or more. Also, the HCDS gas can be moresufficiently adsorbed onto the wafer 200 by increasing the temperatureof the wafer 200 to 300 degrees C. or more, and a more sufficient filmforming rate can be obtained. Further, when the temperature of the wafer200 exceeds 700 degrees C., film thickness uniformity may be easilydeteriorated to make it difficult to control the film thicknessuniformity as a CVD reaction is strengthened (a gaseous reaction becomesdominant). Deterioration of the film thickness uniformity can besuppressed, and thus, it is possible to control the film thicknessuniformity by setting the temperature of the wafer 200 to 700 degrees C.or less. In particular, a surface reaction becomes dominant by settingthe temperature of the wafer 200 to 650 degrees C. or less, the filmthickness uniformity can be easily secured, and thus, it becomes easy tocontrol the film thickness uniformity. Accordingly, the temperature ofthe wafer 200 may be set to fall within a range of 250 to 700 degreesC., or more specifically, for example, 300 to 650 degrees C.

The supply of the HCDS gas causes the silicon-containing layer having athickness, for example, of less than one atomic layer to several atomiclayers to be formed on the uppermost surface of the wafer 200 modifiedby the NH₃ gas in the surface modification step and having the firstcarbon-containing layer formed in the portion thereof. Accordingly, afirst layer containing silicon and carbon, i.e., a layer including thefirst carbon-containing layer and the silicon-containing layer, isformed on the uppermost surface of the wafer 200. The silicon-containinglayer may be an adsorption layer of the HCDS gas or a silicon layer (Silayer), or include both of them. However, the silicon-containing layermay be a layer containing silicon (Si) and chlorine (Cl).

Here, the silicon layer is a generic name including a discontinuouslayer as well as a continuous layer constituted by silicon (Si), or asilicon thin film formed by laminating the discontinuous layer and thecontinuous layer constituted by Si. Also, in some cases, a continuouslayer constituted by Si may be referred to as the silicon thin film. Inaddition, Si constituting the silicon layer includes Si, in whichbonding to Cl is not completely broken.

Moreover, the adsorption layer of the HCDS gas includes a chemisorptionlayer in which gas molecules of the HCDS gas are discontinuous, inaddition to a chemisorption layer in which the gas molecules of the HCDSgas are continuous. That is, the adsorption layer of the HCDS gasincludes a chemisorption layer having a thickness of one molecular layercontaining HCDS molecules or less than one molecular layer. Further,HCDS (Si₂Cl₆) molecules constituting the adsorption layer of the HCDSgas also contains molecules in which bonding of Si and Cl is partiallybroken (Si_(x)Cl_(y) molecules). That is, the adsorption layer of theHCDS includes a chemisorption layer in which Si₂Cl₆ molecules and/orSi_(x)Cl_(y) molecules are continuous, or a chemisorption layer in whichSi₂Cl₆ molecules and/or Si_(x)Cl_(y) molecules are discontinuous. Also,a layer having a thickness of less than one atomic layer refers to adiscontinuously formed atomic layer, and a layer having a thickness ofone atomic layer refers to a continuously formed atomic layer. Inaddition, a layer having a thickness of less than one molecular layerrefers to a discontinuously formed molecular layer, and a layer having athickness of one molecular layer refers to a continuously formedmolecular layer.

Under a condition in which the HCDS gas is autolyzed (pyrolyzed), i.e.,under a condition in which a pyrolysis reaction of the HCDS gas occurs,the silicon layer is formed by depositing Si on the wafer 200. Under acondition in which the HCDS gas is not autolyzed (pyrolyzed), i.e.,under a condition in which a pyrolysis reaction of the HCDS gas does notoccur, the adsorption layer of the HCDS gas is formed by adsorbing theHCDS gas onto the wafer 200. In addition, forming the silicon layer onthe wafer 200 can increase the film forming rate more than forming theadsorption layer of the HCDS gas on the wafer 200. When the thickness ofthe silicon-containing layer formed on the wafer 200 exceeds severalatomic layers, an effect of modification in Steps 4 and 5 describedlater is not applied to the entire silicon-containing layer. Inaddition, a minimum value of the thickness of the silicon-containinglayer that can be formed on the wafer 200 is less than one atomic layer.Accordingly, the thickness of the silicon-containing layer may be lessthan one atomic layer to several atomic layers. In addition, as thethickness of the silicon-containing layer is one atomic layer or less,i.e., one atomic layer or less than one atomic layer, an effect of themodification reaction in Steps 4 and 5 described later can be relativelyincreased, and thus the time required for the modification reaction inSteps 4 and 5 can be reduced. The time for forming thesilicon-containing layer in Step 2 can be reduced. As a result, aprocessing time per one cycle can be reduced, and a total processingtime can also be reduced. That is, the film forming rate can also beincreased. In addition, as the thickness of the silicon-containing layeris one atomic layer or less, controllability of the film thicknessuniformity can also be increased.

(Residual Gas Removal)

After the silicon-containing layer is formed, the valve 243 a of thefirst gas supply pipe 232 a is closed to stop the supply of the HCDSgas. At this time, while the APC valve 244 of the exhaust pipe 231 is inan open state, the interior of the process chamber 201 is vacuumexhausted by the vacuum pump 246, and the HCDS gas remaining in theprocess chamber 201 which does not react or remains after contributingto the formation of the silicon-containing layer or reaction byproductsare removed from the process chamber 201. At this time, the valves 243e, 243 f, 243 g and 243 h are in an open state, and the supply of the N₂gas as the inert gas into the process chamber 201 is maintained. The N₂gas acts as a purge gas, and thus, the HCDS gas remaining in the processchamber 201 which does not react or remains after contributing to theformation of the silicon-containing layer or reaction byproducts can bemore effectively removed from the process chamber 201.

Moreover, in this case, the gas remaining in the process chamber 201 maynot be completely removed, and the interior of the process chamber 201may not be completely purged. When the gas remaining in the processchamber 201 is very small in amount, there is no adverse effectgenerated in Step 3 performed thereafter. Here, an amount of the N₂ gassupplied into the process chamber 201 need not be a large amount, andfor example, approximately the same amount of N₂ gas as the reactiontube 203 (the process chamber 201) may be supplied to perform the purgesuch that there is no adverse effect generated in Step 3. As describedabove, as the interior of the process chamber 201 is not completelypurged, the purge time can be reduced, thereby improving the throughput.In addition, the consumption of the N₂ gas can also be suppressed to aminimal necessity.

The silicon-containing gas may include an inorganic precursor gas suchas a tetrachlorosilane, i.e., silicon tetrachloride (SiCl₄, abbreviatedto STC) gas, trichlorosilane (SiHCl₃, abbreviated to TCS) gas,dichlorosilane (SiH₂Cl₂, abbreviated to DCS) gas, monochlorosilane(SiH₃Cl, abbreviated to MCS) gas, monosilane (SiH₄) gas or the like, aswell as an organic precursor gas such as an aminosilane-based gas,including tetrakis(dimethylamino)silane (Si[N(CH₃)₂]₄, abbreviated to4DMAS) gas, tris(dimethylamino)silane (Si[N(CH₃)₂]₃H, abbreviated to3DMAS) gas, bis(diethylamino)silane (Si[N(C₂H₅)₂]₂H₂, abbreviated to2DEAS) gas, bis(tertiary-butylamino)silane (SiH₂[NH(C₄H₉)]₂, abbreviatedto BTBAS) gas, or the like, in addition to the hexachlorodisilane(Si₂Cl₆, abbreviated to HCDS) gas. The inert gas may include a rare gassuch as Ar gas, He gas, Ne gas, Xe gas, and the like, in addition to theN2 gas.

[Step 3] (C₃H₆ Gas Supply)

After Step 2 is terminated and the residual gas in the process chamber201 is removed, the C₃H₆ gas activated by heat is supplied to the wafer200. A processing sequence and processing conditions in this step aresimilar to the processing sequence and processing conditions when theC₃H₆ gas is supplied in the above-described Step 1.

In this embodiment, the gas flowing into the process chamber 201 is thethermally activated the C₃H₆ gas, and no HCDS gas is allowed to flowinto the process chamber 201. Therefore, the C₃H₆ gas does not cause agas phase reaction and is supplied in an activated state to the wafer200. Further, as a second carbon-containing layer, a carbon-containinglayer having a thickness of less than one molecular layer or less thanone atomic layer, i.e., a discontinuous carbon-containing layer, isformed on the silicon-containing layer formed on the wafer 200 in Step2. Accordingly, a second layer containing silicon and carbon, i.e., alayer including the first carbon-containing layer, thesilicon-containing layer and the second carbon-containing layer, isformed on the uppermost surface of the wafer 200. In addition, dependingon conditions, a portion of the silicon-containing layer reacts with theC₃H₆ gas supplied in Step 3 and the silicon-containing layer is modified(carbonized), so that in some cases, the second layer containing siliconand carbon, i.e., a layer including the first carbon-containing layerand the modified (carbonized) silicon-containing layer, may be formed onthe uppermost surface of the wafer 200.

The second carbon-containing layer formed on the silicon-containinglayer may be a chemisorption layer of the carbon-containing gas (C₃H₆gas), a chemisorption layer of a substance (C_(x)H_(y)) produced bydecomposing C₃H₆, or a carbon layer (C layer). Here, a chemisorptionlayer of C₃H₆ or C_(x)H_(y) needs to be a discontinuous chemisorptionlayer of C₃H₆ molecules or C_(x)H_(y) molecules. Also, the carbon layerneeds to be a discontinuous layer constituted by carbon. In addition,when the second carbon-containing layer formed on the silicon-containinglayer is a continuous layer, for example, when an adsorption of C₃H₆ orC_(x)H_(y) onto the silicon-containing layer is saturated to form acontinuous chemisorption layer of C₃H₆ or C_(x)H_(y) on thesilicon-containing layer, the surface of the silicon-containing layer isentirely covered with the chemisorption layer of C₃H₆ or C_(x)H_(y). Insuch a case, no silicon exists on the surface of the second layer (thelayer including the first carbon-containing layer, thesilicon-containing layer and the second carbon-containing layer),resulting in difficulty in obtaining an oxidation reaction of the secondlayer in Step 4 described later or a nitridation reaction of the secondlayer in Step 5 described later, in some cases. This is the reason whyunder the processing conditions as described above, nitrogen or oxygenis bonded to silicon but is hardly bonded to carbon. In order to cause adesired oxidation or nitridation reaction in Step 4 or 5 describedlater, the adsorption of C₃H₆ or C_(x)H_(y) onto the silicon-containinglayer needs to be unsaturated to expose silicon in the surface of thesecond layer.

In order to unsaturate the adsorption of C₃H₆ or C_(x)H_(y) onto thesilicon-containing layer, the processing conditions in Step 3 need onlybe the above-described processing conditions. However, if the processingconditions in Step 3 are set to the following processing conditions, itbecomes easy to unsaturate the adsorption of C₃H₆ or C_(x)H_(y) onto thesilicon-containing layer.

Wafer Temperature: 500 to 650 degrees C.

Internal Pressure of Process Chamber: 133 to 5332 Pa

Partial Pressure of C₃H₆ Gas: 33 to 5177 Pa

Supply Flow Rate of C₃H₆ Gas: 1000 to 10000 sccm

Supply Flow Rate of N₂ Gas: 300 to 3000 sccm

Supply Time of C₃H₆ Gas: 6 to 200 seconds

(Residual Gas Removal)

After the second carbon-containing layer is formed, the valve 243 b ofthe second gas supply pipe 232 b is closed to stop the supply of theC₃H₆ gas. At this time, while the APC valve 244 of the exhaust pipe 231is in an open state, the interior of the process chamber 201 is vacuumexhausted by the vacuum pump 246, and the C₃H₆ gas remaining in theprocess chamber 201 which does not react or remains after contributingto the formation of the second carbon-containing layer or reactionbyproducts are removed from the process chamber 201. At this time, thevalves 243 f, 243 e, 243 g and 243 f are in an open state, and thesupply of the N₂ gas as the inert gas into the process chamber 201 ismaintained. The N₂ gas acts as a purge gas, and thus, the C₃H₆ gasremaining in the process chamber 201 which does not react or remainsafter contributing to the formation of the second carbon-containinglayer or reaction byproducts can be effectively removed from the processchamber 201.

Moreover, the gas remaining in the process chamber 201 may not becompletely removed, and the interior of the process chamber 201 may notbe completely purged. When the gas remaining in the process chamber 201is very small in amount, there is no adverse effect generated in Step 4performed thereafter. Here, an amount of the N₂ gas supplied into theprocess chamber 201 need not be a large amount, and for example,approximately the same amount of the N₂ gas as the reaction tube 203(the process chamber 201) may be supplied to perform the purge such thatthere is no adverse effect generated in Step 4. As described above, asthe interior of the process chamber 201 is not completely purged, thepurge time can be reduced, thereby improving the throughput. Inaddition, the consumption of the N₂ gas can also be suppressed to aminimal necessity.

The carbon-containing gas may include a hydrocarbon-based gas, such asacetylene (C₂H₂) gas or ethylene (C₂H₄) gas, in addition to thepropylene (C₃H₆) gas.

[Step 4] (O₂ Gas Supply)

After Step 3 is terminated and the residual gas in the process chamber201 is removed, the valve 243 c of the third gas supply pipe 232 c isopened to flow the O₂ gas into the third gas supply pipe 232 c. A flowrate of the O₂ gas flowing in the third gas supply pipe 232 c isadjusted by the mass flow controller 241 c. The flow rate-adjusted O₂gas is supplied into the process chamber 201 through the gas supplyholes 250 c of the third nozzle 249 c. The O₂ gas supplied into theprocess chamber 201 is activated by heat and exhausted through theexhaust pipe 231. In this way, the O₂ gas activated by heat is suppliedto the wafer 200.

At the same time, the valve 243 g is opened to flow the N₂ gas into thethird inert gas supply pipe 232 g. The N₂ gas flowing in the third inertgas supply pipe 232 g is supplied into the process chamber 201 togetherwith the O₂ gas, and exhausted through the exhaust pipe 231. Here, inorder to prevent infiltration of the O₂ gas into the first nozzle 249 a,the second nozzle 249 b, the fourth nozzle 249 d, and the buffer chamber237, the valves 243 e, 243 f and 243 h are opened to flow the N₂ gasinto the first inert gas supply pipe 232 e, the second inert gas supplypipe 232 f, and the fourth inert gas supply pipe 232 h. The N₂ gas issupplied into the process chamber 201 through the first gas supply pipe232 a, the second gas supply pipe 232 b, the fourth gas supply pipe 232d, the first nozzle 249 a, the second nozzle 249 b, the fourth nozzle249 d, and the buffer chamber 237, and exhausted through the exhaustpipe 231.

Here, the APC valve 244 is appropriately adjusted to set the internalpressure of the process chamber 201 to fall within a range of, forexample, 1 to 6000 Pa. A supply flow rate of the O₂ gas controlled bythe mass flow controller 241 c is set to fall within a range of, forexample, 100 to 10000 sccm. A supply flow rate of the N₂ gas controlledby each of the mass flow controllers 241 g, 241 e, 241 f and 241 h isset to fall within a range of, for example, 100 to 10000 sccm. Here, apartial pressure of the O₂ gas in the process chamber 201 is set to fallwithin a range of, for example, 0.01 to 5941 Pa. A duration forsupplying the O₂ gas to the wafer 200, i.e., a gas supply time(irradiation time), is set to fall within a range of, for example, 1 to200 seconds, specifically, for example, 1 to 120 seconds, or morespecifically, for example, 1 to 60 seconds. In this case, in the sameway as Steps 1 to 3, a temperature of the heater 207 is set such that atemperature of the wafer 200 falls within a range of, for example, 250to 700 degrees C., or more specifically, for example, 300 to 650 degreesC. The O₂ gas is thermally activated under the same conditions as above.In addition, since the O₂ gas is activated by heat and supplied togenerate a soft reaction, the oxidation described later can be gentlyperformed.

Here, the gas flowing into the process chamber 201 is the thermallyactivated O₂ gas, and none of the HCDS gas and the C₃H₆ gas is allowedto flow into the process chamber 201. Therefore, the O₂ gas does notcause a gas phase reaction, and the activated O₂ gas is supplied to thewafer 200 and reacts with at least a portion of the second layercontaining silicon and carbon (the layer including the firstcarbon-containing layer, the silicon-containing layer and the secondcarbon-containing layer) formed on the wafer 200 in Step 3. Accordingly,the second layer is thermally oxidized in a non-plasma environment to bechanged (modified) to a third layer containing silicon, oxygen andcarbon, i.e., a silicon oxycarbide layer (SiOC layer).

Here, the oxidation reaction of the second layer should not besaturated. For example, when the first carbon-containing layer having athickness of less than one atomic layer is formed in Step 1, thesilicon-containing layer having a thickness of several atomic layers isformed in Step 2, and the second carbon-containing layer having athickness of less than one atomic layer is formed in Step 3, at least aportion of the surface layer (one atomic layer of the surface) thereofis allowed to be oxidized. In this case, in order not to oxidize theentire second layer, the oxidation is performed under conditions inwhich the oxidation reaction of the second layer is unsaturated.Further, depending on conditions, the oxidation may occur from thesurface layer of the second layer to several layers therebelow. However,it is preferable to oxidize only the surface layer since controllabilityof a composition ratio of the SiOCN film can be improved. In addition,for example, when the first carbon-containing layer having a thicknessof less than one atomic layer is formed in Step 1, thesilicon-containing layer having a thickness of one atomic layer or lessthan one atomic layer is formed in Step 2, and the secondcarbon-containing layer having a thickness of less than one atomic layeris formed in Step 3, a portion of its surface layer is also allowed tobe oxidized. Even in such a case, in order not to oxidize the entiresecond layer, the oxidation is performed under conditions in which theoxidation reaction of the second layer is unsaturated.

Further, for the oxidation reaction of the second layer to beunsaturated, the processing conditions in Step 4 need only be set to theabove-described processing conditions. However, if the processingconditions in Step 4 are set to the following processing conditions, theoxidation reaction of the second layer is easily unsaturated.

Wafer Temperature: 500 to 650 degrees C.

Internal Pressure of Process Chamber: 133 to 5332 Pa

Partial Pressure of O₂ Gas: 12 to 5030 Pa

Supply Flow Rate of O₂ Gas: 1000 to 5000 sccm

Supply Flow Rate of N₂ Gas: 300 to 10000 sccm

Supply Time of O₂ Gas: 6 to 200 seconds

In this embodiment, particularly, oxidizing power in Step 4 can beappropriately reduced by adjusting the above-described processingconditions to increase a dilution rate of the O₂ gas (reduce aconcentration of the O₂ gas), reduce a supply time of the O₂ gas, orreduce a partial pressure of the O₂ gas. As a result, it becomes easierfor the oxidation reaction of the second layer to be unsaturated. Thefilm forming sequence of FIG. 4A illustrates that a partial pressure ofthe O₂ gas is reduced and the oxidizing power is reduced by setting asupply flow rate of the N₂ gas supplied in Step 4 to be larger than asupply flow rate of the N₂ gas supplied in the other steps.

It is easy to suppress the desorption of carbon (C) from the secondlayer in the oxidation process by reducing the oxidizing power in Step4. Since a Si—O bonding has bonding energy higher than a Si—C bonding,the Si—C bonding tends to be broken when the Si—O bonding is formed.However, it is possible to prevent the Si—C bonding from being brokenwhen the Si—O bonding is formed in the second layer by properly reducingthe oxidizing power in Step 4. Thus, it is easy to prevent C, in whichbonding to Si is broken, from being desorbed from the second layer.

In addition, it is possible to maintain an exposed state of Si in thesecond layer after the oxidation, i.e., the uppermost surface of thethird layer, by reducing the oxidizing power in Step 4. As the exposedstate of Si in the uppermost surface of the third layer is maintained,it becomes easy to nitride the uppermost surface of the third layer inStep 5 described later. If the Si—O bonding or the Si—C bonding isformed over the entire uppermost surface of the third layer and Si isnot exposed in the uppermost surface, the Si—N bonding tends to behardly formed under conditions of Step 5 described later. However, it iseasy to form the Si—N bonding by maintaining the exposed state of Si inthe uppermost surface of the third layer, i.e., by allowing Si capableof being bonded to Ni under the conditions of Step 5 described later toexist in the uppermost surface of the third layer.

(Residual Gas Removal)

After the third layer is formed, the valve 243 c of the third gas supplypipe 232 c is closed to stop the supply of the O₂ gas. At this time,while the APC valve 244 of the exhaust pipe 231 is in an open state, theinterior of the process chamber 201 is vacuum exhausted by the vacuumpump 246, and the O₂ gas remaining in the process chamber 201 which doesnot react or remains after contributing to the formation of the thirdlayer or reaction byproducts are removed from the process chamber 201.At this time, the valves 243 g, 243 e, 243 f and 243 h are in an openstate, and the supply of the N₂ gas as the inert gas into the processchamber 201 is maintained. The N₂ gas acts as a purge gas, and thus, theO₂ gas remaining in the process chamber 201 which does not react orremains after contributing to the formation of the third layer orreaction byproducts can be more effectively removed from the processchamber 201.

Moreover, in this case, the gas remaining in the process chamber 201 maynot be completely removed, and the interior of the process chamber 201may not be completely purged. When the gas remaining in the processchamber 201 is very small in amount, there is no adverse effectgenerated in Step 5 performed thereafter. Here, an amount of the N₂ gassupplied into the process chamber 201 need not be a large amount, andfor example, approximately the same amount of the N₂ gas as the reactiontube 203 (the process chamber 201) may be supplied to perform the purgesuch that there is no adverse effect generated in Step 5. As describedabove, as the interior of the process chamber 201 is not completelypurged, the purge time can be reduced, thereby improving the throughput.In addition, the consumption of the N₂ gas can also be suppressed to aminimal necessity.

The oxidizing gas may include water vapor (H₂O) gas, nitrogen monoxide(NO) gas, nitrous oxide (N₂O) gas, nitrogen dioxide (NO₂) gas, carbonmonoxide (CO) gas, carbon dioxide (CO₂) gas, ozone (O₃) gas, hydrogen(H₂) gas+O₂ gas, H₂ gas+O₃ gas, and the like, in addition to the oxygen(O₂) gas.

[Step 5] (NH₃ Gas Supply)

After Step 4 is terminated and the residual gas in the process chamber201 is removed, the NH₃ gas activated by heat is supplied to the wafer200. A processing sequence and processing conditions in this step arealmost the same to the processing sequence and processing conditionswhen the NH₃ gas is supplied in the above-described surface modificationstep. However, a duration for supplying the NH₃ gas to the wafer 200,i.e., a gas supply time (irradiation time), is set to fall within arange of, for example, 1 to 200 seconds, specifically, for example, 1 to120 seconds, or more specifically, for example, 1 to 60 seconds. Also,in Step 5, the NH₃ gas is activated by heat and supplied. Since the NH₃gas is activated by heat and supplied to generate a soft reaction, thenitriding described later can be softly performed. However, in the sameway as the above-described surface modification step, the NH₃ gas may beactivated to plasma and supplied.

Here, the gas flowing into the process chamber 201 is the thermallyactivated NH₃ gas, and none of the HCDS gas, the C₃H₆ gas and the O₂ gasis allowed to flow into the process chamber 201. Therefore, the NH₃ gasdoes not cause a gas phase reaction, and the activated NH₃ gas issupplied to the wafer 200 and reacts with at least a portion of thelayer containing silicon, oxygen and carbon, as the third layer, formedon the wafer 200 in Step 4. Accordingly, the third layer is thermallynitrided in a non-plasma environment to be changed (modified) to afourth layer containing silicon, oxygen, carbon and nitrogen, i.e., asilicon oxycarbonitride layer (SiOCN layer).

Further, in a process of nitriding the third layer by supplying theactivated NH₃ gas to the wafer 200, the uppermost surface of the thirdlayer is modified (surface modification processing). Specifically, asthe NH₃ gas is adsorbed onto the uppermost surface of the third layer,the adsorption layer of the NH₃ gas is formed on the uppermost surfaceof the third layer, i.e., the uppermost surface of the fourth layer.Also, in that time, as the uppermost surface of the third layer reactswith the activated NH₃ gas to be modified, in some cases, a layer havingSi—N bonding, i.e., a nitride layer containing silicon (Si) and nitrogen(N) (silicon nitride layer) may be further formed on the uppermostsurface of the third layer, i.e., the uppermost surface of the fourthlayer. That is, in some cases, both the nitride layer and the adsorptionlayer of the NH₃ gas may be formed on the uppermost surface of the thirdlayer, i.e., the uppermost surface of the fourth layer.

The uppermost surface of the third layer after the surface modificationprocessing is performed in the nitriding process, i.e., the uppermostsurface of the fourth layer, is changed into a surface state in whichthe HCDS gas to be supplied in a next cycle is easily adsorbed and Si iseasily deposited. That is, the NH₃ gas used in Step 5 acts as anadsorption and deposition facilitating gas that facilitates adsorptionor deposition of the HCDS gas or Si onto the uppermost surface of thefourth layer (the uppermost surface of the wafer 200) in the next cycle.

In this embodiment, the nitridation reaction of the third layer shouldnot be saturated. For example, when the third layer having a thicknessof several atomic layers is formed in Steps 1 to 4, at least a portionof the surface layer (one atomic layer of the surface) is allowed to benitrided. In this case, in order not to nitride the entire of the thirdlayer, the nitridation is performed under conditions in which theoxidation reaction of the third layer is unsaturated. Further, dependingon conditions, the nitridation may be allowed to occur from the surfacelayer of the third layer to several layers therebelow. However, it ispossible to nitride only the surface layer since controllability of acomposition ratio of the SiOCN film can be improved thereby. Inaddition, for example, when the third layer having a thickness of oneatomic layer or less than one atomic layer is formed in Steps 1 to 4, aportion of its surface layer is also allowed to be nitrided. Even insuch a case, in order not to nitride the entire of the third layer, thenitridation is performed under conditions in which the nitridationreaction of the third layer is unsaturated.

Further, in order that the nitridation reaction of the third layer isunsaturated, the processing conditions in Step 5 need only be set to theabove-described processing conditions. However, if the processingconditions in Step 5 are set to the following processing conditions, thenitridation reaction of the third layer is easily unsaturated.

Wafer Temperature: 500 to 650 degrees C.

Internal Pressure of Process Chamber: 133 to 5332 Pa

Partial Pressure of NH₃ Gas: 33 to 5030 Pa

Supply Flow Rate of NH₃ Gas: 1000 to 5000 sccm

Supply Flow Rate of N₂ Gas: 300 to 3000 sccm

Supply Time of NH₃ Gas: 6 to 200 seconds

(Residual Gas Removal)

After the fourth layer is formed, the interior of the process chamber201 is vacuum exhausted, and the NH₃ gas remaining in the processchamber 201 which does not react or remains after contributing to theformation of the fourth layer or reaction byproducts are removed fromthe process chamber 201. A processing sequence and processing conditionsin this step are similar to the processing sequence and processingconditions when the residual gas is removed in the above-describedsurface modification step.

In the same way as the surface modification step, the nitriding gas mayinclude diazene (N₂H₂) gas, hydrazine (N₂H₄) gas, N₃H₈ gas, and thelike, in addition to the ammonia (NH₃) gas.

The above-described Steps 1 to 5 may be set as one cycle and the cyclemay be performed once or more (i.e., a predetermined number of times) toform a thin film containing silicon, oxygen, carbon and nitrogen, i.e.,a silicon oxycarbonitride film (SiOCN film), having a predetermined filmthickness. Also, the above-described cycle may be performed multipletimes. That is, it is possible that a thickness of the SiOCN layerformed per cycle be set to be smaller than a desired film thickness, andthe above-described cycle be repeated multiple times until the desiredfilm thickness is obtained.

Further, when the cycle is performed multiple times, in Step 1 duringand after the second cycle, the phrase “the first carbon-containinglayer is formed in a portion of the uppermost surface of the wafer 200modified by the NH₃ gas in the surface modification step” means that“the first carbon-containing layer is formed in a portion of theuppermost surface of the third layer modified by the NH₃ gas in Step 5,i.e., the uppermost surface of the fourth layer,” and the phrase “atleast a portion of the first carbon-containing layer is formed in such amanner that a portion of the NH₃ gas adsorbed onto at least a portion ofthe uppermost surface of the wafer 200 modified by the NH₃ gas in thesurface modification step is substituted by the C₃H₆ gas” means that “atleast a portion of the first carbon-containing layer is formed in such amanner that a portion of the NH₃ gas adsorbed onto at least a portion ofthe uppermost surface of the third layer modified by the NH₃ gas in theStep 5, i.e., the uppermost surface of the fourth layer, is substitutedby the C₃H₆ gas.”

That is, when the cycle is performed multiple times, the phrase “apredetermined gas is supplied to the wafer 200” in each step during andafter at least the second cycle means that a predetermined gas issupplied to a layer formed on the wafer 200, i.e., the uppermost surfaceof the wafer 200, which is a laminated body. The phrase “a predeterminedlayer is formed on the wafer 200” means that a predetermined layer isformed on a layer formed on the wafer 200, i.e., the uppermost surfaceof the wafer 200, which is a laminated body. Also, above-describedmatters are similar in other film forming sequences or their respectivemodifications described later.

In addition, when the SiOCN film is formed in the film forming sequence,the C₃H₆ gas is allowed to be supplied twice per cycle (through theseparate two steps). That is, the C₃H₆ gas is allowed to be suppliedtwice, i.e., before and after Step 2 in which the HCDS gas is supplied(i.e., in Steps 1 and 3). Accordingly, it is possible to control thenitrogen (N) concentration and the carbon (C) concentration in the SiOCNfilm. For example, it is possible to increase the C concentration byreducing the N concentration in the SiOCN film.

Further, when the SiOCN film is formed in the film forming sequence,ratios of the respective element components, i.e., the siliconcomponent, the oxygen component, the carbon component, and the nitrogencomponent, i.e., the silicon concentration, the oxygen concentration,the carbon concentration, and the nitrogen concentration, in the SiOCNlayer, can be adjusted and a composition ratio of the SiOCN film can becontrolled by controlling the processing conditions such as the internalpressure of the process chamber 201 or the gas supply time in each step.

For example, it is possible to control the amount of desorption of theNH₃ gas from the adsorption layer of the NH₃ gas formed on the modifieduppermost surface of the wafer 200 (or the uppermost surface of thefourth layer) or the amount of adsorption of the C₃H₆ gas onto themodified uppermost surface of the wafer 200 (or the uppermost surface ofthe fourth layer) by controlling the gas supply time of the C₃H₆ gas inStep 1 or the partial pressure or concentration of the C₃H₆ gas in theprocess chamber 201 in Step 1. Accordingly, it is possible to finelyadjust the N concentration and the C concentration in the SiOCN film.For example, it is possible to increase the amount of desorption of theNH₃ gas from the adsorption layer of the NH₃ gas formed on the modifieduppermost surface of the wafer 200 (or the uppermost surface of thefourth layer) or to increase the amount of adsorption of the C₃H₆ gasonto the modified uppermost surface of the wafer 200 (or the uppermostsurface of the fourth layer) by increasing the gas supply time of theC₃H₆ gas in Step 1 or increasing the partial pressure or concentrationof the C₃H₆ gas in the process chamber 201 in Step 1. Accordingly, it ispossible to increase the C concentration by reducing the N concentrationin the SiOCN film. However, if the gas supply time of the C₃H₆ gas inStep 1 is excessively long, it is also considered that a film formingrate of the SiOCN film is reduced. Accordingly, the gas supply time ofthe C₃H₆ gas in Step 1 may be set to be equal to or shorter than the gassupply time of the C₃H₆ gas in Step 3, for example.

In addition, for example, it is possible to control the amount ofadsorption of the C₃H₆ gas onto the uppermost surface of the wafer 200(or the uppermost surface of the first layer) in Step 3 or the amount ofoxidation in Step 4 by controlling the gas supply time of the C₃H₆ gasin Step 3 or the partial pressure or concentration of the C₃H₆ gas inthe process chamber 201 in Step 3. Accordingly, it is possible to finelyadjust the C concentration and the O concentration in the SiOCN film.For example, it is possible to properly perform the oxidation reactionin Step 4 since an appropriately exposed state of silicon in the surfaceof the second layer can be maintained by adjusting the gas supply timeor the partial pressure or concentration of the C₃H₆ gas to a suitablevalue in Step 3 to make the adsorption of C₃H₆ onto thesilicon-containing layer be appropriately unsaturated, i.e., to make thesecond carbon-containing layer be an appropriate discontinuous layer.

Consequently, it is possible to appropriately control the Oconcentration, the C concentration, and the N concentration in the SiOCNfilm. For example, it is possible to increase the C concentration byreducing the N concentration while suppressing a reduction in the Oconcentration in SiOCN film. In addition, for example, even when thefilm forming temperature of the SiOCN film is lowered, it is possible tosuppress an increase in the dielectric constant of the SiOCN film orreduce the dielectric constant of the SiOCN film.

(Purge and Return to Atmospheric Pressure)

When the film forming processing of forming the SiOCN film having apredetermined film thickness and a predetermined composition isperformed, the inert gas such as the N₂ gas is supplied into the processchamber 201 and exhausted, whereby the interior of the process chamber201 is purged with the inert gas (gas purge). Thereafter, an atmospherein the process chamber 201 is substituted with the inert gas (inert gassubstitution), and the internal pressure of the process chamber 201returns to the normal pressure (return to atmospheric pressure).

(Boat Unloading and Wafer Discharging)

Thereafter, the seal cap 219 is lowered by the boat elevator 115 to openthe lower end of the reaction tube 203, and the processed wafer 200supported by the boat 217 is unloaded to the outside of the reactiontube 203 through the lower end of the reaction tube 203 (boatunloading). Then, the processed wafer 200 is discharged from the boat217 (wafer discharging).

(Second Sequence)

Next, a second sequence of the embodiment will be described.

FIG. 5A is a view illustrating gas supply timings in the second sequenceof the embodiment.

The second sequence of the embodiment is different from theabove-described first sequence in that a thin film containing thepredetermined element, oxygen, carbon and nitrogen is formed on the awafer 200 by performing a cycle a predetermined number of times, thecycle including performing the following steps in the following order:

supplying a nitriding gas to the wafer 200;

supplying a carbon-containing gas to the wafer 200;

supplying a predetermined element-containing gas to the wafer 200;

supplying the carbon-containing gas to the wafer 200; and

supplying an oxidizing gas to the wafer 200.

In addition, the second sequence of the embodiment is different from theabove-described first sequence in that the process of forming the thinfilm further includes a step of supplying the nitriding gas to the wafer200 after the above-described cycle is performed a predetermined numberof times.

That is, the second sequence of the embodiment is different from theabove-described first sequence in that a thin film containing thepredetermined element, oxygen, carbon and nitrogen is formed on thewafer 200 by performing a cycle a predetermined number of times and thenperforming a step of supplying a nitriding gas to the wafer 200, thecycle including performing the following steps in the following order:

supplying the nitriding gas to the wafer 200;

supplying a carbon-containing gas to the wafer 200;

supplying a predetermined element-containing gas to the wafer 200;

supplying the carbon-containing gas to the wafer 200; and

supplying an oxidizing gas to the wafer 200.

Hereinafter, the second sequence of the embodiment will be described.Here, HCDS gas is used as the predetermined element-containing gas, C₃H₆gas is used as the carbon-containing gas, O₂ gas is used as theoxidizing gas, and NH₃ gas is used as the nitriding gas, and a siliconoxycarbonitride film (SiOCN film) containing silicon, oxygen, carbon andnitrogen is formed on the wafer 200 by the film forming sequence of FIG.5A, i.e., the film forming sequence of performing a cycle apredetermined number of times and then performing a step of supplyingNH₃ gas to the wafer 200, the cycle including performing the followingsteps in the following order: supplying the NH₃ gas, supplying C₃H₆ gas,supplying HCDS gas, supplying the C₃H₆ gas, and supplying O₂ gas.

(Wafer Charging and Wafer Rotation)

Wafer charging, boat loading, pressure adjustment, temperatureadjustment, and wafer rotation are performed in the same way as thefirst sequence.

[Process of Forming Silicon Oxycarbonitride Film]

Five steps described later, i.e., Steps 1 to 5 are set as one cycle. Thecycle is performed once or more, and then a nitriding step describedlater is performed.

[Step 1]

Step 1 of the second sequence is performed similarly to the surfacemodification step or Step 5 of the first sequence. A processing sequenceand processing conditions in Step 1 of the second sequence are similarto the processing sequence and processing conditions in the surfacemodification step or Step 5 of the first sequence.

Also, a reaction caused, a layer formed, and the like in Step 1 in thefirst cycle of the second sequence are similar to those in the surfacemodification step of the first sequence. That is, in this step, theuppermost surface of the wafer 200 is changed (modified) into a surfacestate, in which the HCDS gas is easily adsorbed and Si is easilydeposited, by supplying the activated NH₃ gas to the uppermost surface(base surface when the SiOCN film is formed) of the wafer 200. In otherwords, the adsorption layer of the NH₃ gas is formed on the uppermostsurface of the wafer 200. Furthermore, in some cases, a nitride layercontaining Si and N may be formed on the uppermost surface of the wafer200.

In addition, when the cycle is performed a plurality of times, areaction caused, a layer formed, and the like in Step 1 during and afterthe second cycle of the second sequence are similar to those in Step 5of the first sequence. That is, in this step, a fourth layer containingsilicon, oxygen, carbon and nitrogen is formed on the wafer 200 bysupplying the NH₃ gas into the process chamber 201 to nitride at least aportion of a third layer formed in Step 5 described later. Also, in thisstep, the uppermost surface of the fourth layer which is formed bynitriding the third layer is changed (modified) into a surface state, inwhich the HCDS gas is easily adsorbed and Si is easily deposited, bysupplying the activated NH₃ gas to the surface of the third layer. Thatis, the adsorption layer of the NH₃ gas is formed on the uppermostsurface of the fourth layer. Also, in some cases, along with theadsorption layer of the NH₃ gas, a nitride layer containing Si and N maybe further formed on the uppermost surface of the fourth layer.

[Step 2]

Step 2 of the second sequence is performed similarly to Step 1 of thefirst sequence. A processing sequence, processing conditions, a reactioncaused, a layer formed, and the like in Step 2 of the second sequenceare similar to those in Step 1 of the first sequence. That is, in thisstep, a first carbon-containing layer is formed on the uppermost surfaceof the wafer 200 modified by supplying the NH₃ gas (or the uppermostsurface of the fourth layer) by supplying the C₃H₆ gas into the processchamber 201.

The first carbon-containing layer becomes a layer having a thickness ofless than one molecular layer, i.e., a discontinuous layer, to coveronly a portion of the uppermost surface of the wafer 200 modified by theNH₃ gas in Step 1 (or the uppermost surface of the fourth layer). Thatis, the other portion of the uppermost surface of the wafer 200 modifiedby the NH₃ gas in Step 1 (or the uppermost surface of the fourth layer)is not covered with the first carbon-containing layer to be intactlyexposed and maintains a surface state in which the HCDS gas supplied inStep 3 described later is easily adsorbed and Si is easily deposited.

[Step 3]

Step 3 of the second sequence is performed similarly to Step 2 of thefirst sequence. A processing sequence, processing conditions, a reactioncaused, a layer formed, and the like in Step 3 of the second sequenceare similar to those in Step 2 of the first sequence. That is, in thisstep, a silicon-containing layer having a thickness of, for example,less than one atomic layer to several atomic layers, is formed on theuppermost surface of the wafer 200 modified by the supply of the NH₃ gasand having the first carbon-containing layer formed in the portionthereof (or the uppermost surface of the fourth layer) by supplying theHCDS gas into the process chamber 201. Accordingly, a first layercontaining silicon and carbon, i.e., a layer including the firstcarbon-containing layer and the silicon-containing layer, is formed onthe uppermost surface of the wafer 200 (or the uppermost surface of thefourth layer).

[Step 4]

Step 4 of the second sequence is performed similarly to Step 3 of thefirst sequence. A processing sequence, processing conditions, a reactioncaused, a layer formed, and the like in Step 4 of the second sequenceare similar to those in Step 3 of the first sequence. That is, in thisstep, a second carbon-containing layer is formed on thesilicon-containing layer formed in Step 3 by supplying C₃H₆ gas into theprocess chamber 201. Accordingly, a second layer containing silicon andcarbon, i.e., a layer including the first carbon-containing layer, thesilicon-containing layer and the second carbon-containing layer, isformed on the uppermost surface of the wafer 200 (or the uppermostsurface of the fourth layer).

[Step 5]

Step 5 of the second sequence is performed similarly to Step 4 of thefirst sequence. A processing sequence, processing conditions, a reactioncaused, a layer formed, and the like in Step 5 of the second sequenceare similar to those in Step 4 of the first sequence. That is, in thisstep, a third layer containing silicon, oxygen and carbon is formed onthe wafer 200 by supplying the O₂ gas into the process chamber 201 tooxidize at least a portion of the second layer (the layer including thefirst carbon-containing layer, the silicon-containing layer and thesecond carbon-containing layer).

The above-described Steps 1 to 5 may be set as one cycle and the cyclemay be performed once or more to form a SiOCN film having apredetermined film thickness. Also, the above-described cycle may beperformed a plurality of times. That is, it is possible that a thicknessof the SiOCN layer formed per cycle may be set to be smaller than adesired film thickness, and the above-described cycle may be repeated aplurality of times until the desired film thickness is obtained.

In addition, when the SiOCN film is formed in this film formingsequence, the C₃H₆ gas is allowed to be supplied twice per cycle(through the separate two steps). That is, the C₃H₆ gas is allowed to besupplied twice, i.e., before and after Step 3 in which the HCDS gas issupplied (i.e., in Steps 2 and 4). Accordingly, it is possible tocontrol the nitrogen (N) concentration and the carbon (C) concentrationin the SiOCN film.

Further, when the SiOCN film is formed in this film forming sequence,ratios of the silicon component, the oxygen component, the carboncomponent, and the nitrogen component in the SiOCN layer can beadjusted, and a composition ratio of the SiOCN film can be controlled bycontrolling the processing conditions such as the internal pressure ofthe process chamber 201 or the gas supply time in each step. Forexample, it is possible to finely adjust the N concentration and the Cconcentration in the SiOCN film by controlling the gas supply time ofthe C₃H₆ gas in Step 2 or the partial pressure or concentration of theC₃H₆ gas in the process chamber 201 in Step 2. In addition, for example,it is possible to finely adjust the C concentration and the Oconcentration in the SiOCN film by controlling the gas supply time ofthe C₃H₆ gas in Step 4 or the partial pressure or concentration of theC₃H₆ gas in the process chamber 201 in Step 4. Consequently, it ispossible to control the O concentration, the C concentration, and the Nconcentration in the SiOCN film.

Also, the third layer, i.e., the SiOC layer, is formed on the uppermostsurface of the SiOCN film formed in this process.

[Nitriding Step]

After the Steps 1 to 5 are set as one cycle and the cycle is performed apredetermined number of times, the nitriding step is performed. Thenitriding step of the second sequence is performed similarly to Step 5of the first sequence. A processing sequence, processing conditions, areaction caused, a layer formed, and the like in the nitriding step ofthe second sequence are similar to those in Step 5 of the firstsequence. That is, in this step, the third layer is changed (modified)into the fourth layer, i.e., a SiOCN layer, by supplying the NH₃ gasinto the process chamber 201 to nitride at least a portion of the thirdlayer (SiOC layer) formed on the uppermost surface of the wafer 200 inthe previous cycle. As the uppermost surface of the SiOCN film isappropriately nitrided and modified by the nitriding step, the SiOCNfilm becomes a film formed by laminating SiOCN layers from a lowermostlayer to an uppermost layer. That is, the SiOCN film is a film having auniform composition in the film thickness direction.

(Gas Purge to Wafer Discharging)

After the formation of the SiOCN film and the modification of theuppermost surface of the SiOCN film are performed, the gas purging, thesubstitution with the inert gas, the returning to the atmosphericpressure, the boat unloading, and the wafer discharging are performedsimilarly to the first sequence.

(3) Effects According to the Embodiment

According to the embodiment, one or a plurality of effects is providedas described below.

(a) According to the embodiment, in either of the film formingsequences, before the silicon-containing layer is formed by supplyingthe HCDS gas to the wafer 200, a process of modifying the uppermostsurface of the wafer 200 into a surface state, in which the HCDS gas iseasily adsorbed and Si is easily deposited, by supplying the NH₃ gas tothe wafer 200 and a process of forming the first carbon-containing layerin a portion of the uppermost surface of the wafer 200 by supplying theC₃H₆ gas to the wafer 200 are performed in this order. In addition, thefirst carbon-containing layer is made a discontinuous layer which coversonly the portion of the uppermost surface of the wafer 200 modified bythe NH₃ gas. That is, the other portion of the uppermost surface of thewafer 200 modified by the NH₃ gas is not covered with the firstcarbon-containing layer, and is in an exposed state as it is to maintaina surface state in which the HCDS gas is easily adsorbed and Si iseasily deposited. In addition, until the process of supplying the HCDSgas after the process of forming the first carbon-containing layer, noother process is performed. Accordingly, the film forming rate of theSiOCN film can be increased, thereby improving productivity of the filmforming process even in a low temperature range.

That is, in the first sequence, Steps 1 to 5 are set as one cycle andthe cycle is performed a predetermined number of times, after thesurface modification step, in which the uppermost surface of the wafer200 is modified into a surface state in which the HCDS gas is easilyadsorbed and Si is easily deposited, is performed. Here, the firstcarbon-containing layer formed in Step 1 is made a discontinuous layer,which covers only a portion of the uppermost surface of the wafer 200which is modified. Also, Step 3 of supplying the C₃H₆ gas and Step 4 ofsupplying the O₂ gas are not performed between Steps 1 and 2. As Step 3or 4 is not performed between Steps 1 and 2, the other portion (theexposed surface) of the uppermost surface of the wafer 200, which is notcovered with the first carbon-containing layer, maintains a surfacestate in which the HCDS gas is easily adsorbed and Si is easilydeposited. Accordingly, in Step 2, it is preferred to perform theadsorption of the HCDS gas or the deposition of Si onto the uppermostsurface of the wafer 200, thereby facilitating the formation of thesilicon-containing layer on the uppermost surface of the wafer 200.

Also, in the first sequence, when Steps 1 to 5 are set as one cycle andthe cycle is performed a plurality of times, in the respective stepsduring and after the second cycle, Step 5 of modifying the uppermostsurface of the fourth layer into a surface state in which the HCDS gasis easily adsorbed and Si is easily deposited, Step 1 of forming thefirst carbon-containing layer, and Step 2 of forming thesilicon-containing layer are sequentially performed in this order. Here,the first carbon-containing layer formed in Step 1 is made adiscontinuous layer, which covers only a portion of the uppermostsurface of the fourth layer which is modified. Also, Step 3 of supplyingthe C₃H₆ gas and Step 4 of supplying the O₂ gas are not performedbetween Steps 1 and 2. As Step 3 or 4 is not performed between Steps 1and 2, the other portion (the exposed surface) of the uppermost surfaceof the fourth layer, which is not covered with the firstcarbon-containing layer, maintains a surface state in which the HCDS gasis easily adsorbed and Si is easily deposited. Accordingly, in Step 2,it is preferred to perform the adsorption of the HCDS gas or thedeposition of Si onto the uppermost surface of the fourth layer, therebyfacilitating the formation of the silicon-containing layer on theuppermost surface of the fourth layer.

Also, in the second sequence, when Steps 1 to 5 are set as one cycle andthe cycle is performed a predetermined number of times, in therespective steps in the first cycle, Step 1 of modifying the uppermostsurface of the wafer 200 into a surface state in which the HCDS gas iseasily adsorbed and Si is easily deposited, Step 2 of forming the firstcarbon-containing layer, and Step 3 of forming the silicon-containinglayer are sequentially performed in this order. Here, the firstcarbon-containing layer formed in Step 2 is made a discontinuous layer,which covers only a portion of the uppermost surface of the wafer 200which is modified. Also, Step 4 of supplying the C₃H₆ gas and Step 5 ofsupplying the O₂ gas are not performed between Steps 2 and 3. As Step 4or 5 is not performed between Steps 2 and 3, the other portion (theexposed surface) of the uppermost surface of the wafer 200, which is notcovered with the first carbon-containing layer, maintains a surfacestate in which the HCDS gas is easily adsorbed and Si is easilydeposited. Accordingly, in Step 3, it is preferred to perform theadsorption of the HCDS gas or the deposition of Si onto the uppermostsurface of the wafer 200, thereby facilitating the formation of thesilicon-containing layer on the uppermost surface of the wafer 200.

Also, in the second sequence, when Steps 1 to 5 are set as one cycle andthe cycle is performed a plurality of times, in the respective stepsduring and after the second cycle, Step 1 of modifying the uppermostsurface of the fourth layer into a surface state in which the HCDS gasis easily adsorbed and Si is easily deposited, Step 2 of forming thefirst carbon-containing layer, and Step 3 of forming thesilicon-containing layer are sequentially performed in this order. Here,the first carbon-containing layer formed in Step 2 is made adiscontinuous layer, which covers only a portion of the uppermostsurface of the fourth layer which is modified. Also, Step 4 of supplyingthe C₃H₆ gas and Step 5 of supplying the O₂ gas are not performedbetween Steps 2 and 3. As Step 4 or 5 is not performed between Steps 2and 3, the other portion (the exposed surface) of the uppermost surfaceof the fourth layer, which is not covered with the firstcarbon-containing layer, maintains a surface state in which the HCDS gasis easily adsorbed and Si is easily deposited. Accordingly, in Step 3,it is preferred to perform the adsorption of the HCDS gas or thedeposition of Si onto the uppermost surface of the fourth layer, therebyfacilitating the formation of the silicon-containing layer on theuppermost surface of the fourth layer.

In this way, in either of the film forming sequences, it is possible tofacilitate the formation of the silicon-containing layer on theuppermost surface of the wafer 200. As a result, even in a lowtemperature range, the film forming rate of the SiOCN film can beincreased, thereby improving productivity of the film forming process.

(b) According to the embodiment, when the SiOCN film is formed, the C₃H₆gas is allowed to be supplied twice per cycle (through the separate twosteps). That is, in the first sequence, the C₃H₆ gas is allowed to besupplied twice before and after Step 2 in which the HCDS gas is supplied(i.e., in Steps 1 and 3). In addition, in the second sequence, the C₃H₆gas is allowed to be supplied twice before and after Step 3 in which theHCDS gas is supplied (i.e., in Steps 2 and 4). Accordingly, it ispossible to control the nitrogen (N) concentration and the carbon (C)concentration in the SiOCN film. For example, it is possible to increasethe C concentration by reducing the N concentration in the SiOCN film.(c) According to the embodiment, ratios of the respective elementcomponents, i.e., the silicon component, the oxygen component, thecarbon component, and the nitrogen component, i.e., the siliconconcentration, the oxygen concentration, the carbon concentration, andthe nitrogen concentration, in the SiOCN film, can be adjusted and acomposition ratio of the SiOCN film can be controlled by controlling theprocessing conditions such as the internal pressure of the processchamber or the gas supply time in each step of the respective sequences.In addition, according to the embodiment, since a SiOCN film having apredetermined composition can be formed, etching resistance, dielectricconstant, and insulation resistance can be controlled, which makes itpossible to form a silicon insulating film having a low dielectricconstant, good etching resistance, and good insulation resistance ascompared with a SiN film.

For example, in the first sequence, it is possible to control the amountof desorption of the NH₃ gas from the adsorption layer of the NH₃ gasformed on the modified uppermost surface of the wafer 200 (or theuppermost surface of the fourth layer) or the amount of adsorption ofthe C₃H₆ gas onto the modified uppermost surface of the wafer 200 (orthe uppermost surface of the fourth layer) by controlling the gas supplytime of the C₃H₆ gas in Step 1 or the partial pressure or concentrationof the C₃H₆ gas in the process chamber 201 in Step 1. Accordingly, it ispossible to finely adjust the N concentration and the C concentration inthe SiOCN film. For example, it is possible to increase the amount ofdesorption of the NH₃ gas from the adsorption layer of the NH₃ gasformed on the modified uppermost surface of the wafer 200 (or theuppermost surface of the fourth layer) or to increase the amount ofadsorption of the C₃H₆ gas onto the modified uppermost surface of thewafer 200 (or the uppermost surface of the fourth layer) by increasingthe gas supply time of the C₃H₆ gas in Step 1 or increasing the partialpressure or concentration of the C₃H₆ gas in the process chamber 201 inStep 1. Accordingly, it is possible to increase the C concentration byreducing the N concentration in the SiOCN film.

Also, in the first sequence, it is possible to control the amount ofadsorption of the C₃H₆ gas onto the uppermost surface of the wafer 200(or the uppermost surface of the first layer) in Step 3 or the amount ofoxidation in Step 4 by controlling the gas supply time of the C₃H₆ gasin Step 3 or the partial pressure or concentration of the C₃H₆ gas inthe process chamber 201 in Step 3. Accordingly, it is possible to finelyadjust the C concentration and the O concentration in the SiOCN film.For example, it is possible to properly perform the oxidation reactionin Step 4 since an appropriately exposed state of silicon in the surfaceof the second layer can be maintained by adjusting the gas supply timeor the partial pressure or concentration of the C₃H₆ gas to a suitablevalue in Step 3 to make the adsorption of C₃H₆ onto thesilicon-containing layer be appropriately unsaturated, i.e., to make thesecond carbon-containing layer be an appropriate discontinuous layer.

Also, in the second sequence, it is possible to control the amount ofdesorption of the NH₃ gas from the adsorption layer of the NH₃ gasformed on the modified uppermost surface of the wafer 200 (or theuppermost surface of the fourth layer) or the amount of adsorption ofthe C₃H₆ gas onto the modified uppermost surface of the wafer 200 (orthe uppermost surface of the fourth layer) by controlling the gas supplytime of the C₃H₆ gas in Step 2, or the partial pressure or concentrationof the C₃H₆ gas in the process chamber 201 in Step 2. Accordingly, it ispossible to finely adjust the N concentration and the C concentration inthe SiOCN film. For example, it is possible to increase the amount ofdesorption of the NH₃ gas from the adsorption layer of the NH₃ gasformed on the modified uppermost surface of the wafer 200 (or theuppermost surface of the fourth layer) or to increase the amount ofadsorption of the C₃H₆ gas onto the modified uppermost surface of thewafer 200 (or the uppermost surface of the fourth layer) by increasingthe gas supply time of the C₃H₆ gas in Step 2 or increasing the partialpressure or concentration of the C₃H₆ gas in the process chamber 201 inStep 2. Accordingly, it is possible to increase the C concentration byreducing the N concentration in the SiOCN film.

Also, in the second sequence, it is possible to control the amount ofadsorption of the C₃H₆ gas onto the uppermost surface of the wafer 200(or the uppermost surface of the first layer) in Step 4 or the amount ofoxidation in Step 5 by controlling the gas supply time of the C₃H₆ gasin Step 4 or the partial pressure or concentration of the C₃H₆ gas inthe process chamber 201 in Step 4. Accordingly, it is possible to finelyadjust the C concentration and the O concentration in the SiOCN film.For example, it is possible to properly perform the oxidation reactionin Step 5 since an appropriately exposed state of silicon in the surfaceof the second layer can be maintained by adjusting the gas supply timeor the partial pressure or concentration of the C₃H₆ gas to a suitablevalue in Step 4 to make the adsorption of the C₃H₆ onto thesilicon-containing layer be appropriately unsaturated, i.e., to make thesecond carbon-containing layer be an appropriate discontinuous layer.

Consequently, it is possible to appropriately control the Oconcentration, the C concentration, and the N concentration in the SiOCNfilm. For example, it is possible to increase the C concentration byreducing the N concentration while suppressing a reduction in the Oconcentration in SiOCN film. In addition, for example, even when thefilm forming temperature of the SiOCN film is lowered, it is possible tosuppress an increase in the dielectric constant of the SiOCN film orreduce the dielectric constant of the SiOCN film.

Also, when increasing the gas supply time of the C₃H₆ gas in Step 3 ofthe first sequence or increasing the partial pressure or concentrationof the C₃H₆ gas in the process chamber 201 in Step 3, the amount ofsilicon present in the surface of the second layer (the layer includingthe first carbon-containing layer, the silicon-containing layer and thesecond carbon-containing layer) is reduced to suppress the progress ofthe oxidation reaction of the second layer in Step 4. As a result, theoxygen (O) concentration in the SiOCN film tends to be reduced. Also, inthe same way, even when increasing the gas supply time of C₃H₆ gas inStep 4 of the second sequence or increasing the partial pressure orconcentration of the C₃H₆ gas in the process chamber 201 in Step 4, theamount of silicon present in the surface of the second layer (the layerincluding the first carbon-containing layer, the silicon-containinglayer and the second carbon-containing layer) is reduced to suppress theoxidation reaction of the second layer in Step 5. As a result, theoxygen (O) concentration in the SiOCN film tends to be reduced. Also, insuch cases, it is difficult to reduce the nitrogen (N) concentration inthe SiOCN film, and the carbon (C) concentration is difficult toincrease by a large amount. That is, in these cases, it is difficult toreduce the dielectric constant of the SiOCN film.

(d) According to the embodiment, in either of the film formingsequences, when the process of forming the SiOCN film is completed, thestep of supplying the NH₃ gas is performed at the end. That is, in thefirst film forming sequence, the activated NH₃ gas is supplied to thewafer 200 in Step 5 that is performed at the end of each cycle. Also, inthe second film forming sequence, after the cycle including Steps 1 to 5is performed a predetermined number of times, the nitriding step ofsupplying the activated NH₃ gas to the wafer 200 is performed.Accordingly, the uppermost surface of the SiOCN film can beappropriately nitrided to be modified, thereby making the finally formedSiOCN film a film having a uniform composition in the film thicknessdirection.(e) According to the embodiment, it is possible to obtain theabove-described effects without changing a structure of an existingsubstrate processing apparatus, film forming temperatures, types ofgases, flow rates, and the like only by rearranging the supply order ofthe gases as in the above-described first or second sequence.

In addition, in an early stage of the studies, the inventors thoughtthat if a layer having Si—C bonding was oxidized and then nitrided, notSiOCN but SiO or SiON would be formed. This is the reason why theythought that since Si—O bonding has bonding energy higher than the Si—Nbonding or Si—C bonding, if a layer having the Si—C bonding is oxidized,the Si—C bonding of the layer having the Si—C bonding is broken when theSi—O bonding is formed in the oxidation process to desorb C, in which abonding to Si is broken, from the layer having the Si—C bonding, and itis difficult to form the Si—N bonding even by nitriding the layerthereafter. Accordingly, it was thought that for example, if the supplyorder of the gases is rearranged as in the above-described first orsecond sequence, all C is desorbed, thereby making it impossible to forma SiOCN film (a SiO or SiON film is formed). However, as a result ofrepeated intensive studies, the inventors found that when a layer havingthe Si—C bonding is oxidized and then nitrided, it is possible to have Cremained thereon, which is desorbed from the layer having the Si—Cbonding by the oxidization, by controlling the oxidizing power(particularly, dilution rate, supply time, or partial pressure of anoxidizing gas) and also to properly form the Si—N bonding by thenitriding thereafter, whereby SiOCN can be appropriately formed.According to the film forming sequence of the embodiment, it is possibleto obtain the above-described effects at low cost without much changingthe existing substrate processing apparatus.

(f) According to the embodiment, a SiOCN film having a good in-planeuniformity of a film thickness of a wafer can be formed in either of thefirst and the second sequences. In addition, when a SiOCN film formedaccording to the first or second sequence of the embodiment is used asan insulating film, it is possible to provide an in-plane uniformperformance of the SiOCN film and therefore to contribute to theimprovement of performance of semiconductor devices or the improvementof production yield.(g) In the surface modification step and Steps 1 to 5 of the firstsequence or Steps 1 to 5 and the nitriding step of the second sequenceaccording to the embodiment, the HCDS gas, the C₃H₆ gas, the O₂ gas, andthe NH₃ gas supplied into the process chamber 201 are respectivelyactivated by heat and supplied to the wafer 200. Accordingly, theabove-described respective reactions can be softly performed, and thus,the formation of the silicon-containing layer, the formation of thecarbon-containing layer, the oxidizing processing, and the nitridingprocessing can be easily performed with good controllability.(h) When the silicon insulating film formed by the method of theembodiment is used as a sidewall spacer, a device forming techniquehaving a small leak current and good machinability can be provided.(i) When the silicon insulating film formed by the method of theembodiment is used as an etching stopper, a device forming techniquehaving good machinability can be provided.(j) According to the embodiment, the silicon insulating film having anideal stoichiometric mixture ratio can be formed without using plasma.In addition, since the silicon insulating film can be formed withoutusing plasma, the embodiment may be applied to a process havingprobability of plasma damage, for example, an SADP film of DPT.

Additional Embodiments of the Present Disclosure

Hereinabove, various embodiments of the present disclosure have beenspecifically described, but the present disclosure is not limited to theabove-described embodiment, and may be variously modified withoutdeparting from the spirit of the present disclosure.

For example, although in the above-described first sequence, after thestep of supplying the NH₃ gas (the surface modification step) isperformed, the cycle including performing the step of forming the firstcarbon-containing layer by supplying the C₃H₆ gas (Step 1), the step ofsupplying the HCDS gas (Step 2), the step of forming the secondcarbon-containing layer by supplying the C₃H₆ gas (Step 3), the step ofsupplying the O₂ gas (Step 4), and the step of supplying the NH₃ gas(Step 5) in this order is performed a predetermined number of times, thepresent disclosure is not limited thereto. For example, as amodification of the first sequence is illustrated in FIG. 4B, after thesurface modification step is performed, a cycle including performingSteps 1, 2, 4, 3 and 5 in this order may be performed a predeterminednumber of times. That is, the step of forming the secondcarbon-containing layer by supplying the carbon-containing gas (Step 3)and the step of supplying the oxidizing gas (Step 4) may beinterchangeably performed, e.g., may be performed one prior to theother. However, the first sequence of FIG. 4A in which Step 3 isperformed prior to Step 4 is preferable since it may increase the filmforming rate as compared with the first sequence of FIG. 4B in whichStep 4 is performed prior to Step 3.

Also, for example, although in the above-described second sequence,after the cycle including performing the step of supplying the NH₃ gas(Step 1), the step of forming the first carbon-containing layer bysupplying the C₃H₆ gas (Step 2), the step of supplying the HCDS gas(Step 3), the step of forming the second carbon-containing layer bysupplying the C₃H₆ gas (Step 4), and the step of supplying the O₂ gas(Step 5) in this order is performed a predetermined number of times, thestep of supplying the NH₃ gas (the nitriding step) is performed, thepresent disclosure is not limited thereto. For example, as amodification of the second sequence is illustrated in FIG. 5B, a cycleincluding performing Steps 1, 2, 3, 5 and 4 in this order may beperformed a predetermined number of times and then the nitriding step isperformed. That is, the step of forming the second carbon-containinglayer by supplying the carbon-containing gas (Step 4) and the step ofsupplying the oxidizing gas (Step 5) may be interchangeably performed,e.g., may be performed one prior to the other. However, the secondsequence of FIG. 5A in which Step 4 is performed prior to Step 5 ispreferable since it may increase the film forming rate as compared withthe second sequence of FIG. 5B in which Step 5 is performed prior toStep 4.

Also, for example, the NH₃ gas may be directly supplied into the processchamber 201 through the fourth nozzle 249 d without installing thebuffer chamber 237 in the process chamber 201. In this case, if the gassupply holes 250 d of the fourth nozzle 249 d are configured to face thecenter of the reaction tube 203, the NH₃ gas can be directly supplied tothe wafer 200 through the fourth nozzle 249 d. In addition, only thebuffer chamber 237 may be installed without installing the fourth nozzle249 d.

Moreover, for example, the C₃H₆ gas, the O₂ gas, and the NH₃ gassupplied into the process chamber 201 are not limited to being activatedby heat, and they may be plasma-activated, for example. In this case,for example, using a plasma source as the above-described plasmagenerator, each gas may be plasma-excited. When each gas isplasma-excited and supplied, there is an advantage in that the filmforming temperature can be more lowered. However, when each gas is notplasma-excited but activated by heat as in the above-describedembodiment, to be supplied, there are advantages in that particles canbe prevented from being generated in the process chamber 201 and plasmadamage to members or the wafer 200 in the process chamber 201 can beavoided.

Further, for example, in Step 4 of the first sequence or Step 5 of thesecond sequence, a reducing gas such as a hydrogen-containing gas may besupplied along with the oxidizing gas. Under the processing conditionsof the above-described embodiment, if the oxidizing gas and the reducinggas are supplied into the process chamber 201, which is under anatmosphere of less than atmospheric pressure (negative pressure), theoxidizing gas and the reducing gas react in the process chamber 201 toproduce a moisture (H₂O)-free oxidizing species containing oxygen suchas atomic oxygen, and the oxidizing species oxidizes each layer. In thiscase, the oxidation may occur with high oxidizing power as compared witha case in which only the oxidizing gas is used to oxidize the layers.Such oxidation is performed under a negative pressure atmosphere ofnon-plasma. The reducing gas may include, for example, hydrogen (H₂)gas.

In addition, for example, while an example in which the SiOCN film(semiconductor insulating film) containing silicon that is asemiconductor element is formed as the thin film has been described inthe above-described embodiments, the present disclosure may be appliedto an example in which a metal oxycarbonitride film (metal insulatingfilm) containing a metal element, such as titanium (Ti), zirconium (Zr),hafnium (Hf), tantalum (Ta), aluminum (Al), molybdenum (Mo), gallium(Ga) and germanium (Ge), is formed.

For example, the present disclosure may be applied to the formation of atitanium oxycarbonitride film (TiOCN film), a zirconium oxycarbonitridefilm (ZrOCN film), a hafnium oxycarbonitride film (HfOCN film), atantalum oxycarbonitride film (TaOCN film), an aluminum oxycarbonitridefilm (AlOCN film), a molybdenum oxycarbonitride film (MoOCN film), agallium oxycarbonitride film (GaOCN film), a germanium oxycarbonitridefilm (GeOCN film), or a metal oxycarbonitride film of a combination ormixture thereof.

In this case, by using a precursor gas containing a metal element (ametal element-containing gas) such as a titanium precursor gas, azirconium precursor gas, a hafnium precursor gas, a tantalum precursorgas, an aluminum precursor gas, a molybdenum precursor gas, a galliumprecursor gas, a germanium precursor gas instead of the siliconprecursor gas of the above-described embodiments, the film formation maybe performed by the sequence (the first sequence, the second sequence orthe modification thereof) of the above-described embodiments.

That is, in this case, after a step of supplying a nitriding gas to awafer, a cycle including performing a step of supplying acarbon-containing gas to the wafer, a step of supplying a metalelement-containing gas to the wafer, a step of supplying acarbon-containing gas to the wafer, a step of supplying a oxidizing gasto the wafer, and a step of supplying a nitriding gas to the wafer inthis order is performed a predetermined number of times, thereby forminga thin film containing the metal element, oxygen, carbon and nitrogen(metal oxycarbonitride film) on the wafer.

Also, in this case, after a cycle including performing a step ofsupplying a nitriding gas to a wafer, a step of supplying acarbon-containing gas to the wafer, a step of supplying a metalelement-containing gas to the wafer, a step of supplying acarbon-containing gas to the wafer, and a step of supplying a oxidizinggas to the wafer in this order may be performed a predetermined numberof times, a step of supplying a nitriding gas to the wafer may beperformed, thereby forming a thin film containing the metal element,oxygen, carbon and nitrogen (metal oxycarbonitride film) on the wafer.

For example, when a TiOCN film is formed as the metal oxycarbonitridefilm, a precursor containing Ti may include an organic precursor such astetrakis(ethylmethylamino)titanium (Ti[N(C₂H₅)(CH₃)]₄, abbreviated toTEMAT), tetrakis(dimethylamino)titanium (Ti[N(CH₃)₂]₄, abbreviated toTDMAT), or tetrakis(diethylamino)titanium (Ti[N(C₂H₅)₂]₄, abbreviated toTDEAT), or an inorganic precursor such as titanium tetrachloride(TiCl₄). The gases of the above-described embodiments may be used as thecarbon-containing gas, the oxidizing gas or the nitriding gas. Inaddition, although processing conditions in this case may be similar,for example, to the processing conditions of the above-describedembodiments, it is more preferable that a wafer temperature be set tofall within a range of, for example, 100 to 500 degrees C. and aninternal pressure of the process chamber be set to fall within a rangeof, for Example 1 to 3000 Pa.

Also, for example, when a ZrOCN film is formed as the metaloxycarbonitride film, a precursor containing Zr may include an organicprecursor such as tetrakis(ethylmethylamino)zirconium(Zr[N(C₂H₅)(CH₃)]₄, abbreviated to TEMAZ),tetrakis(dimethylamino)zirconium (Zr[N(CH₃)₂]₄, abbreviated to TDMAZ),or tetrakis(diethylamino)zirconium (Zr[N(C₂H₅)₂]₄, abbreviated toTDEAZ), or an inorganic precursor such as zirconium tetrachloride(ZrCl₄). The gases of the above-described embodiments may be used as thecarbon-containing gas, the oxidizing gas or the nitriding gas. Inaddition, although processing conditions in this case may be similar,for example, to the processing conditions of the above-describedembodiments, it is more preferable that a wafer temperature be set tofall within a range of, for example, 100 to 400 degrees C. and aninternal pressure of the process chamber be set to fall within a rangeof, for Example 1 to 3000 Pa.

In addition, for example, when a HfOCN film is formed as the metaloxycarbonitride film, a precursor containing Hf may include an organicprecursor such as tetrakis(ethylmethylamino)hafnium (Hf[N(C₂H₅)(CH₃)]₄,abbreviated to TEMAH), tetrakis(dimethylamino)hafnium (Hf[N(CH₃)₂]₄,abbreviated to TDMAH), or tetrakis(diethylamino)hafnium (Hf[N(C₂H₅)₂]₄,abbreviated to TDEAH), or an inorganic precursor such as hafniumtetrachloride (HfCl₄). The gases of the above-described embodiments maybe used as the carbon-containing gas, the oxidizing gas or the nitridinggas. In addition, although processing conditions in this case may besimilar, for example, to the processing conditions of theabove-described embodiments, it is more preferable that a wafertemperature be set to fall within a range of, for example, 100 to 400degrees C. and an internal pressure of the process chamber be set tofall within a range of, for Example 1 to 3000 Pa.

Further, for example, when a TaOCN film is formed as the metaloxycarbonitride film, a precursor containing Ta may include an organicprecursor such as tertiary-butylimino tris(diethylamino)tantalum(Ta[N(C₂H₅)₂]₃[NC(CH₃)₃], abbreviated to TBTDET), or tertiary-butyliminotris(ethylmethylamino)tantalum (Ta[NC(CH₃)₃][N(C₂H₅)CH₃]₃), abbreviatedto TBTEMT), or an inorganic precursor such as tantalum pentachloride(TaCl₅). The gases of the above-described embodiments may be used as thecarbon-containing gas, the oxidizing gas or the nitriding gas. Inaddition, although processing conditions in this case may be similar,for example, to the processing conditions of the above-describedembodiments, it is more preferable that a wafer temperature be set tofall within a range of, for example, 100 to 500 degrees C. and aninternal pressure of the process chamber be set to fall within a rangeof, for Example 1 to 3000 Pa.

Furthermore, for example, when a AlOCN film is formed as the metaloxycarbonitride film, a precursor containing Al may include an organicprecursor such as trimethyl aluminum (Al(CH₃)₃, abbreviated to TMA), oran inorganic precursor such as trichloro aluminum (AlCl₃). The gases ofthe above-described embodiments may be used as the carbon-containinggas, the oxidizing gas or the nitriding gas. In addition, althoughprocessing conditions in this case may be similar, for example, to theprocessing conditions of the above-described embodiments, it is morepreferable that a wafer temperature be set to fall within a range of,for example, 100 to 400 degrees C. and an internal pressure of theprocess chamber be set to fall within a range of, for Example 1 to 3000Pa.

Moreover, for example, when a MoOCN film is formed as the metaloxycarbonitride film, a precursor containing Mo may include an inorganic precursor such as molybdenum pentachloride (MoCl₅). The gases ofthe above-described embodiments may be used as the carbon-containinggas, the oxidizing gas or the nitriding gas. In addition, althoughprocessing conditions in this case may be similar, for example, to theprocessing conditions of the above-described embodiments, it is morepreferable that a wafer temperature be set to fall within a range of,for example, 100 to 500 degrees C. and an internal pressure of theprocess chamber be set to fall within a range of, for Example 1 to 3000Pa.

As described above, the present disclosure may also be applied toformation of the metal oxycarbonitride film, in which case functionaleffects similar to the above-described embodiments are obtained. Thatis, the present disclosure may be applied to a case in which theoxycarbonitride film containing a predetermined element such as asemiconductor element or a metal element is formed.

Moreover, while an example in which the thin film is formed using abatch type substrate processing apparatus in which a plurality ofsubstrates are processed at a time has been described, the presentdisclosure is not limited thereto but may be applied to a case in whichthe thin film is formed using a single-wafer type substrate processingapparatus in which one or several substrates are processed at a time.

Moreover, the film forming sequences of the above-described embodiments,the modifications, the application examples and the like may beappropriately combined and used.

In addition, the present disclosure is implemented by modifying, forexample, an existing process recipe of the substrate processingapparatus. When the process recipe is modified, the process recipeaccording to the present disclosure may be installed to the existingsubstrate processing apparatus through an electrical communication lineor a recording medium in which the process recipe is recorded, or theprocess recipe itself may be changed to the process recipe according tothe present disclosure by manipulating an input/output device of theexisting substrate processing apparatus.

EXAMPLES Example 1

As an example of the present disclosure, a SiOCN film was formed on awafer by the first sequence of the above-described embodiment using thesubstrate processing apparatus of the above-described embodiment. FIG.6A is a view illustrating gas supply timings in this example. The HCDSgas was used as the silicon-containing gas, the C₃H₆ gas was used as thecarbon-containing gas, the O₂ gas was used as the oxidizing gas, and theNH₃ gas was used as the nitriding gas. The gas supply time of the C₃H₆gas in Step 1 of forming a first carbon-containing layer was variedwithin the processing range described in the above-described embodimentto manufacture four types of samples. The other processing conditionswere set to fall within a range of the processing conditions describedin the above-described embodiment. In addition, for each samplemanufactured, an oxygen (O) concentration, a nitrogen (N) concentration,and a carbon (C) concentration in the SiOCN film were respectivelymeasured.

FIG. 7 is a graph showing measurement results of the O, N and Cconcentrations of the SiOCN film in Example 1. The vertical axis of FIG.7 represents the O, N and C concentrations (at %) in the film, and thetransverse axis represents the gas supply time (a.u.) of the C₃H₆ gas.In the graph, the mark “” represents the O concentration in the film,the mark “▪” represents the N concentration in the film, and the mark“Δ” represents the C concentration in the film. Referring to FIG. 7,even when the gas supply time of the C₃H₆ gas was increased in Step 1,it can be seen that the O concentration in the SiOCN film is hardlychanged. In addition, it can be seen that the N concentration in theSiOCN film is reduced and the C concentration is increased by increasingthe gas supply time of the C₃H₆ gas in Step 1. That is, it can be seenthat the dielectric constant of the SiOCN film can be reduced byincreasing the gas supply time of the C₃H₆ gas in Step 1. That is, itcan be seen that the N and C concentrations in the SiOCN film can becontrolled (finely adjusted) by controlling the gas supply time of theC₃H₆ gas in Step 1, thereby controlling (finely adjusting) thedielectric constant of the SiOCN film.

Example 2

As an example of the present disclosure, a SiOCN film was formed on awafer by the first sequence of the above-described embodiment using thesubstrate processing apparatus of the above-described embodiment. FIG.6A is a view illustrating gas supply timings in this example. The HCDSgas was used as the silicon-containing gas, the C₃H₆ gas was used as thecarbon-containing gas, the O₂ gas was used as the oxidizing gas, and theNH₃ gas was used as the nitriding gas. The processing conditions in eachstep were set to fall within a range of the processing conditionsdescribed in the above-described embodiment. In addition, O, N and Cconcentrations in the SiOCN film formed on the wafer were respectivelymeasured.

In addition, as a first comparative example, using the substrateprocessing apparatus of the above-described embodiment, after a surfacemodification step of supplying the NH₃ gas to a wafer was performed, acycle including performing Step 1 of supplying the hydrogen (H₂) gas tothe wafer, Step 2 of supplying the HCDS gas to the wafer, Step 3 ofsupplying the C₃H₆ gas to wafer, Step 4 of supplying the O₂ gas to thewafer, and Step 5 of supplying the NH₃ gas to the wafer in this orderwas performed a predetermined number of times, thereby forming a SiOCNfilm on the wafer. The first comparative example was different fromExample 2 only in that the gas used in Step 1 was replaced with the H₂gas, and the processing conditions in each step were set to be equal tothe processing conditions in each step of Example 2. In addition, O, Nand C concentrations in the SiOCN film formed on the wafer wererespectively measured.

In addition, as a second comparative example, using the substrateprocessing apparatus of the above-described embodiment, after a surfacemodification step of supplying the NH₃ gas to a wafer was performed, acycle including performing Step 1 of supplying the nitrogen (N₂) gas tothe wafer, Step 2 of supplying the HCDS gas to the wafer, Step 3 ofsupplying the C₃H₆ gas to wafer, Step 4 of supplying the O₂ gas to thewafer, and Step 5 of supplying the NH₃ gas to the wafer in this orderwas performed a predetermined number of times, thereby forming a SiOCNfilm on the wafer. The second comparative example was different fromExample 2 only in that the gas used in Step 1 was replaced with the N₂gas, and the processing conditions in each step were set to be equal tothe processing conditions in each step of Example 2. In addition, O, Nand C concentrations in the SiOCN film formed on the wafer wererespectively measured.

FIG. 8 is a graph showing measurement results of the O, N and Cconcentrations of the SiOCN film in Example 2 and the first and secondcomparative examples. The vertical axis of FIG. 8 represents the O, Nand C concentrations (at %) in the film, and the transverse axisrepresents the types of the gases used in Step 1. In the graph, the mark“” represents the O concentration in the film, the mark “▪” representsthe N concentration in the film, and the mark “Δ” represents the Cconcentration in the film. Referring to FIG. 8, it can be seen that theO concentration in the film in Example 2 is not changed as compared withthe O concentration in the film in each comparative example. Inaddition, it can be seen that the N concentration in the film in Example2 is low as compared with the N concentration in the film in eachcomparative example. Also, it can be seen that the C concentration inthe film in Example 2 is high as compared with the C concentration inthe film in each the comparative example. That is, it can be seen thatif the C₃H₆ gas is used in Step 1, it is possible to increase the Cconcentration in the film by reducing the N concentration in the filmwhile suppressing a reduction in the O concentration in the SiOCN film,whereby the dielectric constant of the SiOCN film can be reduced. Thatis, it can be seen that if the C₃H₆ gas is used in Step 1, the N and Cconcentrations in the SiOCN film can be controlled (finely adjusted).

Reference Example 1

As Reference Example 1, using the substrate processing apparatus of theabove-described embodiment, after a surface modification step ofsupplying the NH₃ gas to a wafer was performed, a cycle includingperforming Step 1a of supplying the HCDS gas to the wafer, Step 2a ofsupplying the C₃H₆ gas to wafer, Step 3a of supplying the O₂ gas to thewafer, and Step 4a of supplying the NH₃ gas to the wafer in this orderwas performed a predetermined number of times, thereby forming a SiOCNfilm on the wafer. FIG. 6B is a view illustrating gas supply timings inReference Example 1. Reference Example 1 was different from the firstsequence of the above-described embodiment only in that Step 1 offorming the first carbon-containing layer was not performed. Aprocessing sequence or processing conditions in Steps 1a to 4a ofReference Example 1 were set to be similar to the processing sequence orprocessing conditions in Steps 2 to 5 of the first sequence of theabove-described embodiment. In addition, the wafer temperature (filmforming temperature) when a film was formed was varied between 550 to630 degrees C. to manufacture three types of samples, and O, N and Cconcentrations in the SiOCN film formed on the wafer were respectivelymeasured.

FIG. 9 is a graph showing measurement results of the O, N and Cconcentrations of the SiOCN film in Reference Example 1. The verticalaxis of FIG. 9 represents the O, N and C concentrations (at %) in thefilm, and the transverse axis represents the wafer temperature. In thegraph, the mark “” represents the O concentration in the film, the mark“▪” represents the N concentration in the film, and the mark “Δ”represents the C concentration in the film. Referring to FIG. 9, it canbe seen that if the film forming temperature is lowered, the O and Cconcentrations in the SiOCN film are respectively reduced and the Nconcentration is increased. That is, if the film forming temperature islowered, a composition of the SiOCN film approaches that of the SiNfilm, and thus, the dielectric constant of the SiOCN film is increased.

Reference Example 2

As Reference Example 2, using the substrate processing apparatus of theabove-described embodiment, a SiOCN film was formed on a wafer by a filmforming sequence similar to Reference Example 1. Reference Example 2 wasdifferent from the first sequence of the above-described embodiment onlyin that Step 1 of forming the first carbon-containing layer was notperformed as in Reference Example 1. A processing sequence or processingconditions in Steps 1a to 4a of Reference Example 2 were set to besimilar to the processing sequence or processing conditions in Steps 2to 5 of the first sequence of the above-described embodiment. Inaddition, the gas supply time of the C₃H₆ gas in Step 2a was varied tomanufacture three types of samples, and O, N and C concentrations in theSiOCN film formed on the wafer were respectively measured.

FIG. 10 is a graph showing measurement results of the O, N and Cconcentrations of the SiOCN film in Reference Example 2. The verticalaxis of FIG. 10 represents the O, N and C concentrations (at %) in thefilm, and the transverse axis represents the gas supply time (a.u.) ofthe C₃H₆ gas. In the graph, the mark “” represents the O concentrationin the film, the mark “▪” represents the N concentration in the film,and the mark “Δ” represents the C concentration in the film. Referringto FIG. 10, it can be seen that if the gas supply time of the C₃H₆ gasin Step 2a is increased, the O concentration in the SiOCN film isreduced. It can also be seen that even when the gas supply time of theC₃H₆ gas in Step 2a is increased, the N concentration in the SiOCN filmis not reduced, and the C concentration ends up in a slight increase.That is, it can be seen that in the film forming sequence shown in FIG.6B, since the N concentration in the SiOCN film cannot be reduced evenwhen the gas supply time of the C₃H₆ gas in Step 2a is increased, andrastic increase in the C concentration cannot be expected, and thus, itis difficult to reduce the dielectric constant of the SiOCN film.

Further Additional Aspects of the Present Disclosure

Hereinafter, some aspects of the present disclosure will be additionallystated.

According to an aspect of the present disclosure, there is provided amethod of manufacturing a semiconductor device, including forming a thinfilm containing a predetermined element, oxygen, carbon, and nitrogen ona substrate by performing a cycle a predetermined number of times aftersupplying a nitriding gas to the substrate, the cycle includingperforming the following steps in the following order:

supplying a carbon-containing gas to the substrate;

supplying a predetermined element-containing gas to the substrate;

supplying the carbon-containing gas to the substrate;

supplying an oxidizing gas to the substrate; and

supplying the nitriding gas to the substrate.

In some embodiments, in the act of forming the thin film, an uppermostsurface of the substrate is modified by supplying the nitriding gas tothe substrate before the cycle is performed a predetermined number oftimes.

In some embodiments, in the act of forming the thin film, a firstcarbon-containing layer is formed in a portion of the uppermost surfaceby supplying the carbon-containing gas to the substrate; a predeterminedelement-containing layer is formed on the uppermost surface modified bythe nitriding gas and having the first carbon-containing layer formed inthe portion thereof by supplying the predetermined element-containinggas to the substrate; a second carbon-containing layer is formed on thepredetermined element-containing layer by supplying thecarbon-containing gas to the substrate; a layer containing thepredetermined element, oxygen and carbon is formed by supplying theoxidizing gas to the substrate to oxidize a layer including the firstcarbon-containing layer, the predetermined element-containing layer andthe second carbon-containing layer; and a layer containing thepredetermined element, oxygen, carbon and nitrogen is formed and anuppermost surface thereof is modified by supplying the nitriding gas tothe substrate to nitride the layer containing the predetermined element,oxygen and carbon.

In some embodiments, the first carbon-containing layer is formed byadsorbing the carbon-containing gas onto the portion of the uppermostsurface modified by the nitriding gas.

In some embodiments, at least a portion of the first carbon-containinglayer is formed by substituting the carbon-containing gas for a portionof the nitriding gas adsorbed onto at least a portion of the uppermostsurface modified by the nitriding gas.

According to another aspect of the present disclosure, there is provideda method of manufacturing a semiconductor device, including forming athin film containing a predetermined element, oxygen, carbon, andnitrogen on a substrate by performing a cycle a predetermined number oftimes, the cycle including performing the following steps in thefollowing order:

supplying a nitriding gas to the substrate

supplying a carbon-containing gas to the substrate;

supplying a predetermined element-containing gas to the substrate;

supplying the carbon-containing gas to the substrate; and

supplying an oxidizing gas to the substrate.

In some embodiments, the act of forming the thin film further includessupplying the nitriding gas to the substrate after performing the cyclea predetermined number of times.

According to still another aspect of the present disclosure, there isprovided a method of manufacturing a semiconductor device, includingforming a thin film containing a predetermined element, oxygen, carbon,and nitrogen on a substrate by performing a cycle a predetermined numberof times and then supplying a nitriding gas to the substrate, the cycleincluding performing the following steps in the following order:

supplying the nitriding gas to the substrate;

supplying a carbon-containing gas to the substrate;

supplying a predetermined element-containing gas to the substrate;

supplying the carbon-containing gas to the substrate; and

supplying an oxidizing gas to the substrate.

In some embodiments, the predetermined element includes a semiconductorelement or a metal element.

In some embodiments, the predetermined element is silicon.

According to yet another aspect of the present disclosure, there isprovided a method of processing a substrate, including forming a thinfilm containing a predetermined element, oxygen, carbon, and nitrogen ona substrate by performing a cycle a predetermined number of times aftersupplying a nitriding gas to the substrate, the cycle includingperforming the following steps in the following order:

supplying a carbon-containing gas to the substrate;

supplying a predetermined element-containing gas to the substrate;

supplying the carbon-containing gas to the substrate;

supplying an oxidizing gas to the substrate; and

supplying the nitriding gas to the substrate.

According to yet another aspect of the present disclosure, there isprovided a substrate processing apparatus, including:

a process chamber configured to accommodate a substrate;

a predetermined element-containing gas supply system configured tosupply a predetermined element-containing gas to the substrate in theprocess chamber;

a carbon-containing gas supply system configured to supply acarbon-containing gas to the substrate in the process chamber;

an oxidizing gas supply system configured to supply an oxidizing gas tothe substrate in the process chamber;

a nitriding gas supply system configured to supply a nitriding gas tothe substrate in the process chamber; and

a control unit configured to control the predeterminedelement-containing gas supply system, the carbon-containing gas supplysystem, the oxidizing gas supply system and the nitriding gas supplysystem such that a thin film containing the predetermined element,oxygen, carbon, and nitrogen is formed on the substrate in the processchamber by performing a cycle a predetermined number of times aftersupplying the nitriding gas to the substrate in the process chamber, thecycle including performing the following steps in the following order:supplying the carbon-containing gas to the substrate in the processchamber; supplying the predetermined element-containing gas to thesubstrate in the process chamber; supplying the carbon-containing gas tothe substrate in the process chamber; supplying the oxidizing gas to thesubstrate in the process chamber; and supplying the nitriding gas to thesubstrate in the process chamber.

According to yet another aspect of the present disclosure, there isprovided a program that causes a computer to perform a process offorming a thin film containing a predetermined element, oxygen, carbon,and nitrogen on a substrate in a process chamber by performing a cycle apredetermined number of times after supplying a nitriding gas to thesubstrate in the process chamber, the cycle including performing thefollowing steps in the following order:

supplying a carbon-containing gas to the substrate in the processchamber;

supplying a predetermined element-containing gas to the substrate in theprocess chamber;

supplying the carbon-containing gas to the substrate in the processchamber;

supplying an oxidizing gas to the substrate in the process chamber; and

supplying the nitriding gas to the substrate in the process chamber.

According to yet another aspect of the present disclosure, there isprovided a non-transitory computer-readable recording medium storing aprogram that causes a computer to perform a process of forming a thinfilm containing a predetermined element, oxygen, carbon, and nitrogen ona substrate in a process chamber by performing a cycle a predeterminednumber of times after supplying a nitriding gas to the substrate in theprocess chamber, the cycle including performing the following steps inthe following order:

supplying a carbon-containing gas to the substrate in the processchamber;

supplying a predetermined element-containing gas to the substrate in theprocess chamber;

supplying the carbon-containing gas to the substrate in the processchamber;

supplying an oxidizing gas to the substrate in the process chamber; and

supplying the nitriding gas to the substrate in the process chamber.

According to a method of manufacturing a semiconductor device, asubstrate processing apparatus and a recording medium of the presentdisclosure, it is possible to suppress a reduction in film forming rateand an increase in dielectric constant when a thin film containing apredetermined element, oxygen, carbon and nitrogen is formed in a lowtemperature range.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosures. Indeed, the novel methods and apparatusesdescribed herein may be embodied in a variety of other forms;furthermore, various omissions, substitutions and changes in the form ofthe embodiments described herein may be made without departing from thespirit of the disclosures. The accompanying claims and their equivalentsare intended to cover such forms or modifications as would fall withinthe scope and spirit of the disclosures.

What is claimed is:
 1. A method of manufacturing a semiconductor device,comprising forming a thin film containing a predetermined element,oxygen, carbon, and nitrogen on a substrate by performing a cycle apredetermined number of times after supplying a nitriding gas to thesubstrate, the cycle comprising performing the following steps in thefollowing order: supplying a carbon-containing gas to the substrate;supplying a predetermined element-containing gas to the substrate;supplying the carbon-containing gas to the substrate; supplying anoxidizing gas to the substrate; and supplying the nitriding gas to thesubstrate.
 2. The method of claim 1, wherein in the act of forming thethin film, an uppermost surface of the substrate is modified bysupplying the nitriding gas to the substrate before the cycle isperformed a predetermined number of times.
 3. The method of claim 2,wherein in the act of forming the thin film, a first carbon-containinglayer is formed in a portion of the uppermost surface by supplying thecarbon-containing gas to the substrate; a predeterminedelement-containing layer is formed on the uppermost surface modified bythe nitriding gas and having the first carbon-containing layer formed inthe portion thereof by supplying the predetermined element-containinggas to the substrate; a second carbon-containing layer is formed on thepredetermined element-containing layer by supplying thecarbon-containing gas to the substrate; a layer containing thepredetermined element, oxygen and carbon is formed by supplying theoxidizing gas to the substrate to oxidize a layer comprising the firstcarbon-containing layer, the predetermined element-containing layer andthe second carbon-containing layer; and a layer containing thepredetermined element, oxygen, carbon and nitrogen is formed and anuppermost surface thereof is modified by supplying the nitriding gas tothe substrate to nitride the layer containing the predetermined element,oxygen and carbon.
 4. The method of claim 3, wherein the firstcarbon-containing layer is formed by adsorbing the carbon-containing gasonto a portion of the uppermost surface modified by the nitriding gas.5. The method of claim 4, wherein the adsorption of thecarbon-containing gas onto the portion of the uppermost surface modifiedby the nitriding gas is unsaturated.
 6. The method of claim 4, whereinat least a portion of the first carbon-containing layer is formed bysubstituting the carbon-containing gas for a portion of the nitridinggas adsorbed onto at least the portion of the uppermost surface modifiedby the nitriding gas.
 7. The method of claim 4, wherein at least aportion of the first carbon-containing layer is a discontinuous layerformed by substituting the carbon-containing gas for a portion of thenitriding gas adsorbed onto at least the portion of the uppermostsurface modified by the nitriding gas.
 8. The method of claim 3, whereinthe first carbon-containing layer and the second carbon-containing layerare discontinuous layers, respectively.
 9. The method of claim 1,wherein the predetermined element comprises a semiconductor element or ametal element.
 10. The method of claim 1, wherein the predeterminedelement comprises silicon.
 11. A substrate processing apparatus,comprising: a process chamber configured to accommodate a substrate; apredetermined element-containing gas supply system configured to supplya predetermined element-containing gas to the substrate in the processchamber; a carbon-containing gas supply system configured to supply acarbon-containing gas to the substrate in the process chamber; anoxidizing gas supply system configured to supply an oxidizing gas to thesubstrate in the process chamber; a nitriding gas supply systemconfigured to supply a nitriding gas to the substrate in the processchamber; and a control unit configured to control the predeterminedelement-containing gas supply system, the carbon-containing gas supplysystem, the oxidizing gas supply system and the nitriding gas supplysystem such that a thin film containing the predetermined element,oxygen, carbon, and nitrogen is formed on the substrate in the processchamber by performing a cycle a predetermined number of times aftersupplying the nitriding gas to the substrate in the process chamber, thecycle comprising performing the following steps in the following order:supplying the carbon-containing gas to the substrate in the processchamber; supplying the predetermined element-containing gas to thesubstrate in the process chamber; supplying the carbon-containing gas tothe substrate in the process chamber; supplying the oxidizing gas to thesubstrate in the process chamber; and supplying the nitriding gas to thesubstrate in the process chamber.
 12. A non-transitory computer-readablerecording medium storing a program that causes a computer to perform aprocess of forming a thin film containing a predetermined element,oxygen, carbon, and nitrogen on a substrate in a process chamber byperforming a cycle a predetermined number of times after supplying anitriding gas to the substrate in the process chamber, the cyclecomprising performing the following steps in the following order:supplying a carbon-containing gas to the substrate in the processchamber; supplying a predetermined element-containing gas to thesubstrate in the process chamber; supplying the carbon-containing gas tothe substrate in the process chamber; supplying an oxidizing gas to thesubstrate in the process chamber; and supplying the nitriding gas to thesubstrate in the process chamber.